Initiative Actions
 
*Ready/Delay Attack: acting later in round. 3.x D&D distinguishes between ‘readying’ (a standard action interrupts foe) and delaying (a larger full round action can be performed, but after the opponent). IMHO if a 'ready' is used to interrupt, this ideally should use some sort of initiative-based mechanic so that (say) attacking people threatening hostages is risky. Covering someone may also be called out as a separate action (JAGS). LegendQuest lets characters using two weapons have separate initiatives for each weapon, hence a ready ("hold") can be used with one weapon while fending with the other.
Games may consider ready or delay to be an action e.g. in Fireborn 'delay' or 'interrupt' [='ready'] count as a characters mental action (characters get 1 mental and a number of physical actions, so a 'delay' will prevent e.g. aiming, defending, ambush or some other options). It lets an interrupting character whose trigger condition doesn't occur convert the action into a 'delay' however, compared to 3E where the action is just lost. Also for interrupt it specifically notes the interrupted target can change their action (e.g. if a sneaking PC successfully -with a quickness check - interrupts and shoots a troll which as they suspected is about to eat an orphan, the troll can change action and attack them instead).
 
*Shoot from hip (literally or not): penalty to hit to get bonus to initiative
 
*Set vs. Charge: hold action (esp. with reach weapon) dealing additional damage vs. charging opponents.
 
*Refocus: taking penalty to boost initiative roll next round. Redundant if actions are permitted to “hold over” between rounds.
 
*Re-roll initiative: Two-Fisted Tales has a 'reroll initiative' action which costs an action (they can't do anything else) but makes everyone reroll their initiative. [note its d10-d10 game mechanic makes a reroll less variable than say D20].

*Abort: for a system where an action is predeclared, dropping this action to do something else (HERO) e.g. ‘abort to defense’.
 
*Drawing a weapon: may be an action, apply an initiative penalty, or apply an attack roll penalty. If it counts as an action it might use up an attack or count as another action type e.g. an 'automatic action' or 'move action'; cost of an attack is worse if characters have only one attack/round (Dragon Warriors) than several (Palladium?).  It tends to have a more severe cost when combat rounds are defined as shorter.
Thrown weapons (knives, throwing axes) may require a “draw” action before each attack.
5E D&D has a more general "Use an Object" action that covers this (usually free as part of another action or movement, but otherwise costing a full action: this is perhaps too vaguely defined as its unclear whether some things, like drawing a shield, are 'free'. Drawing two weapons at once with one action seems to require a feat (?) whereas it could be done with a +1 BAB in 3E).
Note that being unarmed may just cause problems attacking (D&D), or might involve difficulties Parrying as well. In the latter case, being unarmed might be assumed as part of a surprised condition, even if characters normally draw for free on their turn.
Low Fantasy Gaming allows characters using one-handed weapons to switch between these without an action - as a deliberate decision to allow them more flexibility to balance them vs. shield users or large weapon users. Savage Worlds makes larger weapons harder to quick draw, requiring an Agility roll.
 
*Start/Complete Full Round Action: A 3E D&D action, a 'full round action' can be spread over two rounds, using a 'standard action' in each. Used when a character is forbidden a full round of actions, such as when surprised, magically slowed, or you're a zombie.
 
*Mitigate Surprise:(Hackmaster) - a character helps another character with a worse initiative, averaging their initiative scores.

 
Damage Modifying Moves

 *Gain Advantage: Twisting Tunnels has an abstract 'gain advantage' move wherein a character sets themselves up for a better attack - dealing 'major damage' instead of 'minor damage'. One example of this would be get into close combat with a light weapon. Other games with more complex tactical setups would instead add hit, damage or other specific situational modifiers. Also compare Fate's 'create advantage'.

*"Touch" - rules may be specified for just touching a target, usually as part of magical attacks. D&D 3E alters AC (having a 'touch AC'), while AD&D sometimes specifies that armour doesn't apply. 4E D&D has a "Reflex Defense" that is generally lower that AC and is used instead.
BESM adds a flat +3 bonus to attack rolls just to touch rather than deal damage, although it notes this may be cumulative with called shot penalty to hit a specific area for some things.  It also notes that prolonged contact generally means a 'grapple'. Note that normally BESM treats armour as 'damage reduction', so this is an extra rule to simulate D&Ds 'touch attacks' and is in a way being generated by DR (the touching-is-easier effect comes for free in games like 3E D&D, or AD&D, where the to-hit number is modified by armour and you can just ignore it to get the touch AC).

*Pull Punch: declared to reduce damage from an attack. Some systems distinguish between bashing/lethal (the equivalent action changes damage types). A roll may be required e.g. in Palladium (I've heard it suggested the Pull Punch roll in Palladium could also be needed for other tasks, such as a shapeshifted Dragon trying to shake a normal SDC creature's hand without damaging them).
One system (a supers freerpg, I forget the name) allows regulation of damage only in dice rather than exact points to build in some uncertainty (a character with punch damage 5d6 might roll 1d6,2d6,3d6,4d6 or 5d6 to try to get the right damage, but not roll the total and automatically reduce it to “just enough”).
'Pulling an attack' in Mutazoids is automatic and reduces damage by 1/2. Other systems can let a character opt to not add their Strength damage bonus, if any (5E D&D).
See also discussion on critical hits.
 
*Called Shot: attempt to hit a specific body location. May have different penalties depending on which location; might be useful against a specific monster with an “Achilles Heel” in a specific body location. May include “stapling people to walls” (thrown knife through clothing), cutting Z’s in opponent’s foreheads, or nerve strikes. May also include rules for breaking/severing limbs (usually involving damage > some threshold).
Variants: HarnMaster allows a character to choose “zone” (upper, normal or lower) at -10% to hit rather than fully calling a shot; the One Roll Engine’s “count matches” system may give a PC a couple of different hit locations possible off the same roll, at various #s of successes – building a sort of called shot into every attack.
Called shots for vital locations are potentially deadly in many systems; this may be somewhat mitigated by an active parry system (i.e. if the opponent has to take a penalty to hit, they become easier to parry).
Some weapons might have unusual effects on a called shot, e.g. in 2E Complete Fighter a bola can 'Pin/Trip' with a leg attack, entangle arms or make a "head" called shot to hit the neck and strangle an opponent (d3 damage per round).
Different approaches to called shots: 3E D&D generally avoids 'called shots', but characters can learn specific feats that allow similar effects e.g. 'Hamstring' (trade sneak attack for slowed movement).  That limits access to them a lot for most characters in most campaigns ('action points' in e.g. Eberron could give temporary access to feats in games that use them).
Exalted has no 'called shots', but a description involving a particular stab to something could well be part of a stunt, cf. Stunting below.
Called shots cause particular problems in systems that don't have them, since players will often want to try something like this in some special situation, which then becomes a precedent to always stab at the eyes or etc. Large monsters might allow this due to their size making it more feasible. This is something vaguely defined in e.g. Tunnels and Trolls 5E for missiles, which sets missile SRs by object size (Tiny including "eyes, coins or locks of chests"). It would rarely have a problem with ranged called shots being broken since even regular missile shots are incredibly lethal, at a risk of being pounded in return (defense of zero meaning huge damage if you miss, if no friends can help).

*Bypass Armour: called shot variant ignoring some armour worn at expense of a hit penalty (e.g. Shadowrun). (Only applicable where a system use armour variants other than “AC”/armour as target number). Bypassing armour also sometimes occurs as a critical result (Runequest criticals, Earthdawn "armour defeating hits"). Conan D20 has this apply by default for 'finesse fighters' who use Dex to hit.
A variant of this can also be to have a 'find hole in armour' action which is used before another attack. This works better with systems where armour makes a target harder to hit - the time cost replacing a hit penalty. deadEarth has an 'armour bypass' skill - characters with the skill can opt to bypass armour (skipping damage subtract) by adding their attack roll + armour penetration roll vs. 'Improbable' odds (actually not that difficult since since effectively 2x as many dice are rolled).
 
*Backstab: this is sometimes a specific move (AD&D, or may be an extra action that adds a 'sneak attack' bonus. AD&D requires a surprised opponent, while 3E requires an opponent be 'flanked' (have attackers on both sides) or flat-footed (losing Dex mod to AC from either surprise or immobility. 4E streamlined both of these into forms of 'combat advantage'. Backstab can require a specific class feature; it can also apply to anybody as a result of the combat engine - e.g. if to-hit roll success adds to damage, a character automatically does more damage to  enemies if their defense is lowered.  Backstab can require specific weapons i.e. small or 'finesse' weapons (5E D&D); it can give a flat bonus or work as a damage multiplier which favours using large weapons.

*Death Blow: special move to kill (or probably kill) opponent. Move may not exist or may be heavily controlled by a point cost, activation limitation (“Death Blow on a natural 20”), target level (can’t kill opponents greater than level N), or defender saving throw.
 
*Power Attack/Going for Broke: part of a combat action where a character takes a penalty to get a damage bonus; in 3.5 (Power Attack) requires a feat. 5E includes this as 'Great Weapon Master' for big weapons, or with 'Sharpshooter' for ranged. The 5E design essentially rolls together 'Power Attack' and 'Cleave' and is somewhat interesting in that both these effects operate in a complementary way to make sure the feat is largely equally useful in most situations: lots of small opponents bypasses the usefulness of 'extra damage' (if a normal hit would've taken out a foe anyway) but then activates the other 'take down another foe with a bonus action' ability.

In DC Heroes, anyone can use the same mechanic but ‘result points’ include varies forms of effect, not simply damage i.e. spell duration or degree of intimidation could be improved by taking a roll penalty. DC Heroes also the opposite (a plus to hit for less damage) called a “flailing attack”. 4E D&D generates this effect by multiple powers with slight to-hit or damage modifiers (i.e. careful attack for the opposite version). Freerpg Synchronicity uses the mechanic for 'swashbuckling moves' (though IIRC with the penalty applied to a separate roll for swashbuckling rather than the main roll). The same mechanic could possibly also potentially be used to represent e.g. Two Weapon Fighting, with extra damage from the second weapon applying a to-hit penalty.
Pathfinder 2E - in the playtest - apparently has a 'power attack' move where an extra 'action' (from a characters 3 actions/rd) is spent to get an extra damage die, but without any accuracy lost per se - at least, that is the case unless there's another action which could give a to-hit bonus. (The extra action could normally be used for an extra attack, but at a significant penalty).While called power attack still, this actually works very differently.
 
*Knockout/Sap: stuns opponent; effect level or damage may determine how long. This manuever may occasionally be seen designed for story use (capturing the PCs) –but if abusable could also lead to lots of NPCs being laid out and Coup de Grace’d. (also watch out for railroading). In some games may just be a “head” called shot effect.
Low Fantasy Gaming notes unarmed attacks take no extra penalty on knockouts. 2E D&D gave a KO% automatically will unarmed attacks (maybe too good).
 
*Coup de Grace: attack on downed foe. May be automatic or involve increased damage; in systems where damage is increased based on difference between attacker/defender rolls this move isn’t really required (a Defense of 0 automatically increases damage). A coup de grace might automatically kill an opponent, deal increased damage (e.g. in 3.x D&D, an automatic 'critical hit' with a saving throw then required to avoid death, with a badly-scaling damage-based DC), or in games with multiple HP tracks, deliver damage direct to a more critical variety of hit points (e.g. we've used "direct to HP" as a houserule in Palladium previously). A coup de grace might require helplessness, or merely grappling or even just surprise to deliver.
 
*Finishing Move: often a creature dropped to 0 hit points/the death negative threshold for the game may be described as killed in some gruesome way. This is typically just a descriptor, though videogames may hard code a separate manuever that does this (e.g. the Mortal Kombat series), and sometimes a game may include some mechanical benefit e.g. the 'Eviscerator' feat in 3E D&D means  the target is killed so gruesomely that surviving allies are shaken. Conversely a game may have the option to choose between stun/kill at 0 hp.
 
 
Special Attacks
 
*Trick Shot: attempt to do something tricky e.g. bounce an attack off another surface to avoid cover. May also include ‘ranged disarms’.
Apocalypse World has a separate damage rating for 'ricochets' [1-harm], but without much detail on how these are produced (deliberately or accidentally)
 
*Sunder: destroy held object/ other object. Problematic manuever for PCs since it breaks the treasure- still a good ability for monsters. Sometimes treated as a subset of called shot.
D&D 3.x generally allows a Str check to break objects, or can use damage - many other systems just allow damage (in, say, Savage Worlds, there's not a great deal of difference between damage and a Str check - its largely a Wound or nothing). Palladium for example just has SDC for objects (there is no "Strength check" mechanic).  (For comedy value: http://www.herogames.com/forums/topic/84713-granny-versus-a-burglar/
).
Sunder may be a specific weapon ability covering weapons like sword-breakers (e.g. Tunnels & Trolls 5E)
 
*Disarm: opponent drops a weapon/object held. Larger weapons tend to get a bonus to resist (in AD&D requires 2 successful attempts; 3.x gets +4 per size category different, unfortunately making the Greatsword far better than the rapier for disarming...and the polearm the best, since reach negates the Attack of Opportunity). Location it flies to may be determined randomly (scatter die?) or attacker may be permitted to grab; AD&D yses scatter table but Expert disarm variant lets attacker choose exact location. Sometimes permitted with ranged weapons.
Disarm sometimes occurs to an attacker as a result of a critical parry etc. Dungeon World's 'Class Warfare' has a weird 'Hand of Monkey' ability where an unarmoured character gets '2 armour' against hand-held weapons and if this reduces damage to 0, they are disarmed. This damage-based disarm is interesting in that disarm off gets weapon size or Str modifiers, which this system still preserves despite its simplicity. (also interestingly, there's a wielder 'Vorpal Blade: ignores armour' ability - making the weapon too sharp to be disarmed by the monk!)
Disarm with ranged weapons is most often disallowed, or requires some sort of special ability (cf. 'Trick Shot').

*Suppression Fire -included in e.g. Twilight 2000. 'Midnight at the Well of Souls' had (relatedly) "Opportunity Fire" as a separate action, perhaps in part due to having a move phase occuring before Ranged Fire was resolved - Opportunity Fire acted in the earlier section of the round prior to normal ranged attacks.
Shatterzone handles Suppression Fire as a combination 'interaction' attack (Intimidate roll to terrify targets from moving) + an attack (targets must make a manuever roll against the same number to avoid taking damage). Bughunters 'full auto' rule includes opportunity fire by default (a free attack on anyone moving across the area, see full auto).

*Toss: throwing sand in targets’ eyes or glove in their face, etc. May be application of a “dirty tricks” type skill.
 
*Grab: hold or wrestle a monster. At its simplest this may just be an opposed STR roll, but it can get complicated. (Palladium, not having a Str check rule, frequently has grabbing that has a fixed % chance of working - for example, a tentacle monster like a Vampire Intelligence might have a 40% chance of pinning, or Wrestling pins on an 18-20; both ignore the opponent's Str in resolving the grapple, while the creatures Str is vaguely considered in setting the % in the first case).

3.x D&D distinguishes between ‘grappling’ (struggling hand to hand up close) and ‘pinned’ (one side holds the other), and uses modified opposed attack rolls (based off STR with a special size bonus: monsters typically win due to getting more Str, attack bonus from HD up to twice CR, and the size bonus).
A good criticism here is that the 3.x grapple system is complex due to inconsistency - some actions are impossible, some actions require a grapple check instead of the normal roll, some actions require a grapple check as well as the normal roll, some actions have specific limitations.
HERO has a grapple subsystem using STR damage rolls (sum of d6 per 5 points) instead of the usual 3d6 roll that's its default subsystem for attribute checks.
The City of Terrors solitaire for Tunnels and Trolls includes an arm wrestle that actually just uses the normal combat rules (both sides rolling unarmed dice + ST, DEX and LK adds -  T&T combat being an opposed roll in any case).
Other systems may include rules for martial art type joint locks/submission holds, or choke holds. Twilight 2000 uses a system of ‘controlling hits’ based off damage (hits equal to opponent Strength subdue them) while other games count successes or coloured results for effect. May include ‘hostage taking’ rules. Movement may be impossible, require a roll, or subtract opponent STR from movement rate (DC Heroes). Usually includes a “squeeze” type option to damage held target. Initiating the grab may deal damage.
Some weapons might also function-call the grapple rules e.g. mancatchers, armour spikes, nets or bolas.
Grabbing may also include rules for turning an opponent's weapon against them; this could also be indirectly referenced by e.g. telekinetic grab rules.
Grabbing can be a problematic mechanic since STR tends to scale very little with level for characters, even though in some cases how much damage a character needs to be killed increases dramatically. Consequently it can become easier to take out a character by grabbing them than by direct damage.
Grabs are generally a bad position for spellcasters, although 4E and 5E D&D both deliberately opt to make this not a problem; even Pathfinder slightly reduces Grapple effects compared to 3.5.
Some systems (3.x D&D, Lejendary Adventures [demon in quickstart adventure] may give monsters a free grab attack as part of a normal claw attack (or whatever) - "Improved Grab". This may be used to land a follow-up attack for free or with a to-hit bonus - the lion holds you down and then claws you. (3.x adds in various monster special abilities to do this since in it a grab doesn't give the attacker any to-hit advantage).
 
*Grab Item: this can be rolled into either Grabbing or Disarm, normally, or be a separate manuever. Dungeon World has a 'take control of an item' option on one move for using force. Faserip (MSH clone) has rules for this which however often end in item breakage (a normal success breaks an item if either parties' Str is higher than the object's material strength). An implication might be that someone could let go an item (give the attacker a free higher result level) rather than have it break, though AFAIK this isn't explicitly spelt out and so frequently the manuever just doesn't do what its supposed to.

*Choke: choking may be an option under the 'grab' manuever, or distinct. Choking may use subdual damage rules, have special effects, or apply fatigue damage (GURPS, IIRC). As with grapple it may be possible with a weapon (garote).
 
*Throw: Judo style throw; may require martial arts training.
 
*Lift/Throw Object:[/FONT]
Lifting things can happen in most any system, but actually throwing them at people tends to be particularly common as a combat option in superhero RPGs.

(pic from Superbabes RPG)
The 'lift' and 'throw' may be separate manuevers, or just one; DC Heroes as noted under 'shoot' has some of the more detailed rules for actually what you can pick up and how far it goes, although IIRC how the size of the object modifies damage is actually less defined than in Superbabes.

*Attack to off-balance (Superbabes): if successful, opponent is +3 to be hit next round.
 
*Pin Weapon (Clinch) – grab on opponents weapon to hold it in place; user may be able to punch foe with free hand. A two weapon fighter might be able to use this to pin an enemy’s shield in place as well. An Entangle (with a chain weapon) is usually basically the same thing. One old Sorcerer's Apprentice magazine mentions an old viking trick where using a crappy wooden shield lets an opponents' axe get stuck, holding their arm in position for a chop to the wrist- something like a weapon pin using a shield.
 
*Trip (/Unhorse) – knocks opponent to the ground or pulls rider of horse (Ride skill likely to help). May gain bonuses against unaware opponents. May include sweeping e.g. from staff.
Trip in 3E D&D is fairly unpleasant (being prone gives substantial penalties, and also standing up provokes attacks of opportunity) but a character gets a roll to avoid a trip. AD&D 2E includes a bonus to Dex roll if 'unmoving', presumably based on the action a character declared before initiative, whereas 3E has nothing equivalent since 'moving' occurs on an opponents turn rather than continuously, making the modifier largely redundant).
Dragon Age trips automatically with a successful stunt (unless the target is on horseback) but is a very minor debuff (+1 to be hit).
 
*Feint: distract opponent to land extra attack. May allow bonus damage or select hit location (e.g. cutting at head then rapidly at legs).
Zenobia has a particularly odd Feint mechanic:  after winning a combat round a character can opt to save some of their 'combat result' to the next round, where it's lost if the roll fails or becomes extra damage otherwise (damage is actually unchanged on a success as it equals the difference in combat rolls, but a result of 4+ lets a character deal a "Crippling Blow" as well).

*Twisting the blade: fairly Bad Guy trick; typically extra damage but to-hit penalty.
 
*Stand Still:: making an attack (often as an interrupt) to block another character's movement e.g. a 'clothesline' type manuever. Appears more abstractly in 4E D&D (Fighter's Challenge).
 
*Mark:: 4E D&D. Not exactly an attack, this occurs as a rider effect from attacks or other powers, which generally imposes a penalty on a character if they attack someone other than the one currently 'marking' them.

*Shield Push - cf. Bull Rush. A character may be able to push back an opponent using a shield. Shield size may modify the check, and the character might or might not have to move with the attack. May also have a chance of making the target fall over. 3.5 had a feat for this (Shield Slam, a charge effect), while 5E 'Shield Master' (feat) allows a bonus action attempt to shove a target back 5ft. 2E Complete Fighter also had shield push rules, including modifiers to the save based on if the target is moving (if that applied being difficult to work out: one interpretation being that this never applied - since the shield push occurs on the attacker's turn and the defender moves on their turn - although as 2E had a separate action declaration before initiative, the character might be considered 'moving' from the start of the round if that's what they were going to be doing).

Recovery Actions
*Second Wind: the character regains hit points or the like. 4E allows this once/encounter, while FantasyCraft charges action dice for a "Refresh".
 
*Recover – turn spent throwing off a condition. May require some sort of Con roll, etc. (source - JAGS). Treating this as an action may represent a stunlock on a character i.e. if the only action a character can attempt is to try to remove the condition. Savage Worlds lets a character remove a 'shaken' condition as a turn, but with a 'raise' (high roll) letting the character also act normally. (Savage Worlds uses shaken to represent damage as well as effects like intimidation, so 'recover' and 'second wind' are indistinguishable for SW).
"Recover" type actions can become more complicated when designed to remove conditions that reduce number of actions; the manuever has to be written so that a character who has no actions can still attempt it, rather than being locked up indefinitely. A (non-RPG) version of this would be the Ghostbusters boardgame; slimed characters suffer -1 action, a character can remove a 'slimed' token as long as they do no others that turn, but without it counting as an 'action', so that a character totally stunlocked by slime can deslime.

 
*Reload: replacing ammo in crossbow or firearm for additional use. Some systems e.g. Twilight 2000 distinguish reload types by weapons in considerable detail.
 
*Ready Weapon: an action may sometimes be needed to 'ready' a weapon after use (particularly for larger weapons). In 2E D&D (Complete Fighter), a disarm vs. a two-handed weapon caused the target to lose initiative as noted above; a character with multiple attacks could spend one to cancel the initiative penalty next round, or might be reduced to just attempting a punch with their other attack.
'Irregulars' has a 'controlling pause' simple action that cancels recoil penalties on a weapon for the next action. It notes this is 'not actually an action'; any other action (except shooting again with the same weapon) can be performed simultaneously, the important thing being that two shots/bursts not be fired in immediate succession to avoid recoil.
 
*Orientation Roll - MERP has rules for 'orientation rolls' following confusing actions such as a teleport, dive, fall or knockdown. This uses the Moving Manuever table and is modified for Perception, with the result determining how much action is allowed next round (% activity or any bonus reductions).

Standing Up could also perhaps be classed in this group, as well as in Movement.
 
Super Powers etc. type actions

*Use Power - character uses a power.  Individual powers may have different action times, etc.

*Power Stunt: by which I mean, using a power in an unorthodox fashion. Distinct from Pushing (where just the numerical value increases), a 'power stunt' is qualitatively different, an unusual use of a power. See notes under Powers. Games with rules for this include HERO (may cost XP, tricky due to being effects-based), Icons (requiring a power roll against its own rating), Marvel Super Heroes. Power stunts are pretty useful, particularly when used in rarely arising situations - like spiderman using his webs to save another falling character (which probably won't happen often), rather than just a damage-dealing use.

*Recharge Power: some powers may be 'on' without an additional action cost, but then need an action to use again in combat. An example of this would be the 3.5 soulknife's "Psychic Strike" power [move action to recover]. 3.5 psionics also often had powers that used 'psionic focus', recovery of which could be sped up with other character options.
 
*Deactivate Power: some powers don't need to be turned 'on', but it may be useful to turn them off in some circumstances. 3.x D&D for instance notes that it is a standard action to lower 'spell resistance', in order to receive a beneficial spell. Aberrant has a specific 'dormancy' background which lets a character turn off all a characters powers so they can pretend to be human; conversely powers can be made involuntarily continuous as a taint effect (at Taint .

*Cast a spell - using a spell may be a skill roll or could be an automatic class power.
Often casting a spell leaves a character's defense reduced during. (Hackmaster -later version - is interesting in having "spell fatigue" that reduces defense for several segments after the spell, too). See also 'magic' posts.
Using offensive spells often involves an attack roll, despite this spellcasting is usually a distinct action which has its own action time rules e.g. in 5E D&D, 'Extra Attack' wouldn't allow extra attacks with cantrips.
It would be fairly common for the design intention to be that a character make more weapon attacks than spell attacks in a round (some games would let a character make multiple attacks or only 1 spell). In the worst case where both cost '1 action' however, weapon attacks fairly often run into circumstantial problems that can make spells operate faster - drawing a weapon and/or moving might require an action.

*Cast half-action spell (i.e. 2 spells): A spellcaster might be a able to cast 2 spells if those are 'specific' spells. In Dragon Warriors, warlocks get a limited list of spells marked with an * that they can cast two of in the same round, letting them 'power up' faster than other professions, typically 'buff' type spells e.g. darkvision, ignore pain, stat enhancement (perhaps handy for warlocks since their spells have short durations - d20 spell expiry - meaning buffs are less likely to continue running between combats).
D&D 5E lets characters use a spell that's a 'bonus action' but if so, the other spell can only be a cantrip.

*Concentrate on spell - a 'move action' in 3E D&D, or minor action in 4th. In Savage Worlds IIRC concentrating provokes a multi-action penalty on further spellcasting rolls.


Player Actions
*Stunting bonus for description: WUSHU, Exalted. This covers many of the others but is designed from a different perspective. In these games doing difficult/cool things gives characters a description bonus, rather than a penalty; contrast to most systems where doing something tricky probably gives a penalty in exchange for doing something more cool when it succeeds, unless its a particularly appropriate situational thing that warrants a bonus. Stunting is a mechanic that encourages players to do wacky things, rather than a simulational mechanic. In a similar vein, Feng Shui gives characters +1 to hit with shot guns if they make a shotgun loading noise (ka-chick ?).
(cf. stunt as a bonus vs. older-school systems where a "stunt" is a player attempting an action that's mostly outside the known system, requiring DM judgment calls to function).
Stunting encourages players to imagine 'cool' ways they're doing things (which gets a bonus), but not to radically change what they're doing in ways that could change the mechanic being invoked and so accidentally give a penalty. It works better in fairly abstract systems with a few, broadly-defined combat moves.
 
*Use Safety Valve: this is usually not an action in-character as well, but sometimes is e.g. D&D 3.5 complete scoundrel, spending a “luck reroll” counts as an immediate action.
 
*Narrative Editing:
Could be thought of a sort of 'use safety valve' as generally some sort of resource cost is involved.
Cortex+ has 'create asset' as an action, requiring a plot point and adding an extra die. Picking up something to use as a club might count as a create action (if worth an extra die), or it could include having gadgets (related to a characters skills), contacts, etc.

*Argue with the GM: perhaps the slowest combat action of them all. I've included as a player action since if successful it does have an effect on the game, unlike most other IRL player actions (like eating pizza or telling Monty Python jokes).

*Soaking (Savage Worlds): soak in SW burns a "bennie" and so is a subset of using safety valve, really. The damage result changes, but there isn't particularly a clear way of explaining in-character why damage went down. In most systems with soaking, the soak roll is free and perhaps represents how tough the character is, although its unclear what the random factor the dice roll represents. It is also perhaps uncertain why Vigour is the stat used for the roll (since that already factors into Toughness), except that this 'steps up' the effect of the Vigour attribute which has only a slight effect on the [quite variable] damage roll. A roll is used because the designer's didn't like how in their preceding design for Deadlands, characters could automatically not be threatened by damage (from SW's design notes).
 
*Heroic Sacrifice (Icons): An Icons hero can opt to pass on using Determination (safety valve luck points) from a team pool to recover, choosing to remain defeated, which adds an additional Determination point to the pool by "inspiring the rest of the team with his or her sacrifice".

Miscellaneous
 
*Presence Attack/Intimidate/Taunt – turn used to overawe, intimidate or distract foe; may gain initiative, apply attack penalty to foe.
 
*Talk!: (Edited in 6/11/2014, and I can't believe I've missed adding this one as long as I have).  Generally talking is something that isn't covered much by the rules. 3.5 D&D specifies that its a free action that can be performed even when its not your turn (an addition from 3.0) and also mentions it may be disallowed when surprised (so players can kill sentries and such). Excessive talking aka Diplomacy is a full-round action (if done at a -10 penalty)..oddly a character can't move while using Diplomacy by RAW. (Meanwhile, Charm Person is a standard action).
Talking rules may be covered by more complex 'social combat' systems. Dr Who: Adventures in Time and Space has social combat occur in a phase before the physical combat phase (to encourage diplomacy winning the day as in the source material). Exalted has various social charms which however can, reportedly, often be thwarted by just entering combat (encouraging "do not listen to the witch, she lies!" type occurences. Dogs in the Vineyard is designed to begin with talking, then escalate into physical violence (the same combat but adding a bucket more dice into the conflict). [/FONT]

*Spot: roll to notice something untoward – may have separate rules for deliberate spotting vs. reactive.
 
*"Grope": (HarnMaster) this action in HM covers situations like recovering a dropped weapon while attacked or perhaps pulling an impaled weapon out of a foe; uses a Dex check.
 
*Pushing: attempt to briefly increase an attribute -or a super power rating - for a specific effect, such as lifting a weight or running or flying faster/jumping further than normal. Rarely found (usually in supers games e.g. DC Heroes). It often applies to generally diceless actions, and generally use of it implies some sort of attribute-based 'effect' system, a follow-up roll boosted by the pushed score (incompatible with pushing giving a multi-tasking penalty), or at least an ad-hoc ability threshold to perform some action (e.g. 'you need Str 13+ to wield a bastard sword). May require dice roll and/or expenditure of luck points or fatigue points. Uses an Athletics check in FantasyCraft. A variant is also seen in Masterbook.
'Pushing' mechanics could also be used as an umbrella that can cover a number of other situations/combat moves, if the rules are sufficiently integrated. For example, it could be used to handle using a too-heavy weapon (multiaction penalties then apply to weapon use, or a character just has fewer attacks due to action costs), to initiative i.e. going faster then giving a to-hit penalty (if initiative uses the same mechanic as other actions), to movement (i.e. running might be simply a result of spending an action to Push movement).
DC Heroes, while one of few games with this, had particular problems with it due to the logarithmic nature of character stats - the 2E DC Heroes review in Dragon #165 reported that a good die roll in 1E would let Batman lift a DC-9 airplane, though this was fixed.
"Safety valve" mechanics, such as Willpower expenditure in Storyteller, can sometimes fill a similar role.
If pushing requires a roll it is perhaps opposite to 'taking 10', with more effect in exchange for a chance of failure.

*Instinctive Attack: [Runequest] this is a roll by the target under [Con x 1%], to determine if they can continue fighting 'instinctively' after a head shot that should knock them out. (Perhaps not a true 'manuever' but I don't know where else to put this).
 
*Use Casual STR (HERO): the character can use their STR at 1/2 value quickly (zero phase action).
Other attributes are also occasionally used 'casually' e.g. to represent passive use.

*Perform Automatic Action: carry out a minor task that doesn't require a dice roll. In some circumstances automatic actions might become 'dice' actions; Shadowrun 1E for instance gives +1 to Target Numbers if a character is in combat (per opponent), with automatic actions now requiring Quickness rolls against TN 4.
Automatic actions may or may not be 'free' depending on system.
(DC Heroes is one of the more defined systems here, giving one automatic action + one dice action each round).
Perhaps this is a category of actions rather than a specific action.
Automatic actions might belong to a fixed list of 'minor' actions, or what's automatic might vary from character-to-character (e.g. compare 3E D&D's "Take 10" rules; see the "cutting down excess rolling" post).

*Drink Potion: a typical D&D action. The potion drinking may also need to be paired with an action to retrieve the object (e.g. in 3E D&D, which also has 'potion belts' in Forgotten Realms at least, to get rid of the retrieve action).
Time required to drink a potion is sometimes noted to increase e.g. for dying characters (full round action to administer without them choking) or in weightless conditions (Dragon #71 notes it takes 1-4 rounds on the Astral Plane).

*Rage - getting angry for combat bonuses. D&D treats this as a barbarian class feature with a fiddly list of bonuses, useable several times/day at player discretion (with the understanding you 'rage' anytime you want your bonuses). Dragon Warriors likewise has a barbarian class feature, letting characters shift points from Defense into Attack.Gamma World 4E has combat modifiers for rage, but applied at GM discretion when appropriate for the character to be angry. In Star Wars D6 a character may be able to get angrier permanently (Dark side points) in exchange for force points. In oWoD Werewolf all characters have Rage points, operating as a secondary safety valve.

*Situational special stunts ["Improvise Action"]: many systems let characters improvise special moves based on situation, whether swinging on chandeliers or throwing sand in eyes or whatnot (whether something is improvised depends a lot on what options are already covered in the system).  Interesting things here are the stunt systems in D&D 4E ("page 42" in the DMG and its list of guidelines, giving options generally comparable to use of an at-will power) or Feng Shui (which similarly sets penalties based on game mechanics, distinct from in-world description - see page 3 post on effect). This option tends to be poorer for higher-level characters, whose normal fighting, spellcasting, etc. functions are all powered up to heck -4E's system being a good start here (auto-scaled damage at least) but still not enough, and with the idea of special stunts working at cross-purposes to the general design where single rolls are not deadly and most defenses/bonuses scale automatically. Improvise action is less discouraged if increased abilities happen to synergise with whatever the insane plan happens to be.
If other combat actions aren't detailed in depth (old school games), this could end up as a pretty commonly-used maneuver, encompassing e.g. grabs or disarms. Games with incomplete/nontransparent rules could incentivize improvising by making how well it works largely unknown to be player (perhaps even obscuring normal attack's effectiveness as much as possible - AC, monster special abilities, etc.). This option also starts looking particularly good in combat after several rounds of getting nowhere the conventional way.

'Low Fantasy Gaming' is another game that has an action like this - there's a generic "Exploit" action that lets a character do more or less anything - grabs, blinding with a cut over an eye, throwing sand, disarming - with an extra ability check to see if this works. A 'minor' exploit suffers no hit penalties etc. and does normal damage, but once an exploit is failed no further attempts can be made against a target.

Dungeon World has a "Pull a Stunt" manuever that is also similar - options e.g. putting yourself in a position, negate opponent's advantage, taking control of something. Compare to: 'Create Advantage' (FATE, under Cooperative Actions), 'Gain Advantage' (Twisting Tunnels, under Damage Modifying), and "Stunting Bonus for Description" (Exalted, this post).

*Don/Remove armour [components] - usually requires multiple rounds. Time required may vary by armour, or be modifiable by assistance (2E) or item add-ons (3E 'quick release straps', or the Calling magic enhancement).

*Find A Thing:: (doesn't exactly belong in combat but IDK where else to put it). Action to "pull out" a useful objects. Dragonlance Adventures has a 'kender pockets' table, where a kender can attempt to pull out a random object (off a table maintained by the GM for that purpose, starting based off a generic list in the book). Night's Black Agent's reportedly has a "Preparedness" skill, which at higher levels allows a character to declare (retroactively) that they have something useful for the situation; (my Complete 2E AD&D rebuild has something similar as a kit ability for the 'Scavenger', giving them kender pockets but resolved with a Foraging NWP check). (This is also mentioned in the later 'abstraction' post).

*"Mental Default" - Fireborn allows various mental actions (1 per round) as well as various physical. Skipping any other 'mental' action lets a character get a free reroll on a physical action.

*Distract [Chill]- Chill lets' player characters attempt to 'distract' monsters, which lets them make a surprise check; however, this makes characters lose a Luck point permanently which can't be recovered and what they're doing has to be described and allowed by the GM.

*Other minor: A few other misc. very specific manuevers include hammering the opponent into the ground like a nail (Superbabes), pulling an opponent into a punch (combination grab/punch dealing two-handed damage/double damage?(Superbabes), the fastball special (character A throws character B at an opponent; HERO), mount (getting atop grabbed opponent; JAGS), breakfall (Ninjas & Superspies), Beat/Expulsion (briefly slam opponent weapon out of the way; Riddle of Steel – one variant here is attacker and the other defender), half-sword (grasp blade to reduce weapon length; Riddle of Steel; Stop Short - stopping movement quickly to trick opponent (Riddle of Steel), Finesse Throw (LegendQuest- throw using Dex but without adding Str mod to damage, and range halved). A thread here discusses a 'grab shield' manuever (spinning a strapped shield with the resulting force breaking the defender's arm). Shadowrun also has a few matrix-combat related combat actions.

recent edits: improvised action section expanded

This last post for combat (unless I think of anything else) is just a grab bag of things I've not yet mentioned. If there's anything ppl feel I've neglected, feel free to make suggestions.

Poison: may inflict either damage, ability damage, or some weird effect. Traditional D&D had poison nearly always causing death (with a save to negate). Tunnels and Trolls gives poisons a damage multiplier (on weapon damage) rather than fixed damage i.e. curare x2, dragon’s venom x4 (which can generate huge amounts of damage; older T&T added in poison before comparing sides' attack totals so it could also help to hit). Dungeon Worlds' 'class warfare' has a 'Serpents' Tears' poison that lets damage be rolled twice (take highest) though this makes less sense (a scratch should deliver less poison). Freerpg "Dark Passages" by David Johansen gives poison damage 'per level' (to offset D&D-style hit points), and also doesn't give a level bonus to saves, so its equally deadly regardless of level.
Poison may be just an item that's purchaseable, or be a class feature or skill.
Most systems categorize poison as Ingested/Injected/Contact/Inhaled (or something like that). RPGs often have unrealistic onset times for convenience's sake. Elaborations: LegendQuest has a dosage table which lists # doses require to coat a weapon of a given size (from 1 unit for a arrow head, to 3 for a knife, 4 for a ballista bolt or hand axe or 8 for a long sword); extra doses increase the # hits that are effectively poisoned as well i.e. the longsword is poisoned for the next 8 swings.
Many systems allow for a chance of self-poisoning e.g. on weapons fumbles. Some fantasy settings inflict social controls on use of poison (e.g. the death penalty in 1e AD&D, as well as class and alignment restrictions on their use).
Where poisons are all-or-nothing (e.g. auto-death or save-or-die) then defenses against them likewise are usually complete - if you get a resistance to poison its usually "total immunity". Poison that's more complex mechanically has more scope for target number modifiers, damage reductions, etc.


Mass Combat: a few systems include a mass combat system for quickly resolving large numbers of enemies e.g. Basic D&D’s War Machine rules, or the system in “Under the Moons of Zoon”.
If abstract such games may give an army damage based off its size (# troops) and perhaps a random variable with a leader strategy modifier and resolve over a number of rounds, or a really abstract method might just be a few random rolls on tables to determine victory/defeat (e.g. in the Central Casting character background generator books). At the very detailed level, figures may represent “squads” and be played out with something like 3.0 D&D’s Complete Miniatures’ Handbook rules, or the wargame of your choice.  
People have also suggested using the Swarm rules for things like e.g. Orcs in 3.x/4E D&D.
Savage Worlds again is designed for handling large numbers of creatures as part of its regular combat system (monsters are “up, down [shaken], or off the table”), and multiple checks for large numbers of NPCs can be rolled easily e.g. 10 guys shooting arrows might have Shooting d6 each, and so 10d6 can be rolled to find hits – handy for something like pirate ship battles). SW does have the slight problem that as damage is compared against a threshold each time, instead of being subtracted, each damage roll has to be made individually.

Tunnels and Trolls or (I believe) “Forward – to Adventure!” use side-by-side battle systems and so also can resolve large combats fairly quickly.

Using the normal combat procedures for some games, multiple rolls of e.g. d20 can theoretically be streamlined using tables: Dragon Magazine #113 includes a fast-rolling table for D&D hit rolls/saves, where a single d100 roll generates the equivalent number of hits/misses as rolling 20d20 at a given target number. However, this can’t easily determine # of crits/fumbles, only hits/misses.

Other Alternative Combat Systems: a couple of games have optional 'advanced combat' systems which are used for major fights, as well as standard combat rules.
GURPS has various optional books which the GM can use as necessary.
Riddle of Steel has separate Duelling rules IIRC. 2nd Ed. AD&D also had optional 'duelling' rules in a sourcebook, as well as the GM being able to switch between side-based and individual initiative as desired.
Other games may have the option to use miniatures or not, although minis are something more likely to be useful in large-scale battles (lots of mooks), meaning they're not necessarily useful in 'climactic' encounters (not vs. single BBEGs, unless they also have lots of mooks).

Combat Event Rolls: this was an obscure mechanic from Combat & Tactics in 2nd Ed. D&D. The GM would roll on a table each round, which would generate a number of unusual combat results including the battle moving a number of squares in a given
direction, an armour strap breaking, or a weapon getting stuck in a fallen opponent (if applicable).


Surprise: World of Synnibarr has tables for surprise with multiple types of surprise (AA,A,B, C - invisible ambush, invisible, ambush, and sucker punch). Shatterzone has 'partial surprise' (where a character can make defensive actions only) and full surprise (character is useless).
The Fantasy Trip either gives a full free turn or for 'lesser surprise' just gives an automatic win of initiative (for somewhat alert targets).
AD&D allows an attack for each segment of surprise (assuming every blow counts, unlike in its usual minute-long round).

Arenas : "Red Box Hack" has an interesting method of categorizing areas - different "arenas" give a bonus to different weapons or actions e.g. Hazardous (reach weapons), Open (ranged weapons), Tight (light weapons), Dense (heavy weapons) or Neutral (no bonus).

Character capabilities determine whether terrain hazards are a significant threat. These abilities can include: direction finding, ability to forage/hunt food, ability to carry equipment, resistance to environmental extremes (heat or cold), disease or other problems. (Of course, its not necessary for terrain to be a major hassle, particularly in a high powered game).
Spells and specific character abilities that negate terrain as a game challenge include: Teleport (bypasses hazards), flight (same), energy resistance (heat or cold), not needing to eat/drink (e.g. spells such as create water were nerfed on Dark Sun for this reason), unlimited carrying capacity (via bags of holding or vehicles), and skills preventing characters getting lost, and even ability to produce fire magically. Note also:
 
*Fantasy or SF games may have racial options which give more-or-less immunity to some hazards (and/or susceptibility to others); something to think about when balancing these.
 
*Environmental damage is less significant where characters have large reserves of HPs; occasionally systems with level-based HPs have ended up assigning damage to hot/cold conditions that should result in massive depopulation of certain zones. (IIRC, 3.x D&D cold rules would kill most of the population of Finland fairly quickly). Difficulty of rolls to avoid damage or find food will vary depending on the core mechanics of the system (again in 3.x, it may be easy to take-10 and find food or water easily, largely regardless of terrain conditions).
 
*Energy resistance as “damage reduction” is particularly powerful dealing with heat/cold effects. This may be acceptable, but if the effect is excessive note that frostburn treated as a large lump sum of damage infrequently (say, each 10 minutes or hourly) is less affected by this sort of energy resistance than small amounts of round-by-round damage (unless there’s some sort of “minimum successful damage is at least 1” rule). As with armour, energy resistance may also be treated as a chance of resisting an attack/armour bypass, albeit that this has odd effects in other parts of the game (e.g. fire resistance 75% seen in at least one game I can think of [World of Synnibarr]: “3 of those missiles did nothing, but that fourth one was a bitch”!), or even a proportional energy resistance (mechanically annoying, unless you’re doing this by varying target numbers on a dice pool i.e. reducing damage by 70% would mean rolling d10 for each point of base damage, a 4+ negating it ; though if soaking also applies separately, that will operate synergistically and breaks the proportionality).
'Dark Fantasy' gives fires an 'ignition class' determining damage per round, then sets damage from hits and chance of catching fire to 1/4 due to briefness of contact. [something it doesn't consider but that's perhaps raised as a question, is that this is true for e.g. a flaming swords, but a flaming arrow would remain embedded].

*Foraging systems tend to be more detailed in systems where characters are actually likely to starve to death (Interestingly for D&D, while Ranger is popular as a class choice in later 3.x/4E D&D, the wilderness aspect of the concept becomes less important across editions). HarnMaster has extremely detailed Fishing charts (including exact Fish species caught for either fresh or salt water!), as well as foraging rules; it cross-references skill result by expected conditions on a table to determine food found rather than just applying a bonus/penalty to the check, thus reducing food found more severely for harsh terrain; Cadillacs and Dinosaurs lists food availability by terrain type (including heavy seasonal adjustments) as well as detailing the exact amount of meat provided by deceased dinosaurs in their monster descriptions.
 
*In games where characters use vehicles alot (whether modern or SF) miring, mechanical breakdowns, fuel concerns and the like for those can also be critical, as well as the usual food/environment concerns. Of course, certain terrain types may be impassable to some mounts or vehicles e.g. mountains or heavy jungle; others may just slow movement rate.
Cadillacs & Dinosaurs again is one of the better treatments of vehicle-based hex crawling of this sort I have seen , including lists of random encounters based on hex type (jungle, mountains, etc) which directly plug in both monster encounters, NPC encounters and terrain hazards that are detailed e.g. rock slides, volcanic eruptions, earth tremors, earthquakes, subterranean gas, and storms (for those boating adventurers). While alot of other games have rules for similar hazards it succeeded fairly well (IMHO) at bringing those rules forward and making them a focus of the game.
 
*a number of SF games detail various interesting environments (Traveller?GURPS probably has a few sourcebooks for this too...) – dangerous conditions in such games could include more severe temperatures, high/low gravity, toxic or corrosive atmospheres (or suffocants e.g. Argon in StarCluster supplement Sweet Chariot) , atmospheric pressure/vacuum, radiation, and microbes, as well as the usual hostile organisms. Note some games (e.g. Aberrant) give characters massive freezing damage for exposure to space, incorrect as vacuum is actually an excellent insulator, (cf. thermos flasks). http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold

Quote from: Bloody Stupid Johnson;498457
*a number of SF games detail various interesting environments (Traveller?GURPS probably has a few sourcebooks for this too...) – dangerous conditions in such games could include more severe temperatures, high/low gravity, toxic or corrosive atmospheres (or suffocants e.g. Argon in StarCluster supplement Sweet Chariot) , atmospheric pressure/vacuum, radiation, and microbes, as well as the usual hostile organisms. Note some games (e.g. Aberrant) give characters massive freezing damage for exposure to space, incorrect as vacuum is actually an excellent insulator, (cf. thermos flasks). http://tvtropes.org/pmwiki/pmwiki.php/Main/SpaceIsCold

Actually, argon is not a suffocant on Chariot, any more than nitrogen is in Earth's atmosphere. It's a noble gas, and non-reactive, but under high pressure becomes an intoxicant and a poison, like nitrogen - cf. rapture of the deep, nitrogen narcosis - the victim gets both drunk and poisoned. That pressure (4 atmospheres) is reached at approximately 2 kilometers above sea level on Chariot, so normal mammal life is only found at higher elevations.

Also, Sweet Chariot is not a supplement for StarCluster 2, but a full game, using the StarPool dice pool mechanic rather than the percentiles used in StarCluster 2.

-clash

Quote from: flyingmice;498479Actually, argon is not a suffocant on Chariot, any more than nitrogen is in Earth's atmosphere. It's a noble gas, and non-reactive, but under high pressure becomes an intoxicant and a poison, like nitrogen - cf. rapture of the deep, nitrogen narcosis - the victim gets both drunk and poisoned. That pressure (4 atmospheres) is reached at approximately 2 kilometers above sea level on Chariot, so normal mammal life is only found at higher elevations.
 
Also, Sweet Chariot is not a supplement for StarCluster 2, but a full game, using the StarPool dice pool mechanic rather than the percentiles used in StarCluster 2.
 
-clash

Whoops! OK, thanks Clash, cheers.

Quote from: Bloody Stupid Johnson;498630Whoops! OK, thanks Clash, cheers.

No problemo! You're doing a great job so far!

-clash

Sweet Chariot came about because of random tables. Unlike StarCluster 3, first and second edition came with a setting. I generated that setting using tables I created for the purpose then threw away - I created entirely new ones for SC 3. Chariot was the first world in the first system I created, and for years the specter of how a billion people lived on a planet with poisonous atmosphere and too much solar radiation with only steam-level technology bothered the HELL out of me. Sweet Chariot was the result of Albert Bailey and I brainstorming some workable way for that to have happened, and what it all entailed. In the process it became a very fun - and risky - place to game.

-clash

Thanks Clash
 
Thought it warranted a mention as one of the more interesting SF planets I've seen. I hadn't known the background, more proof of what they say about how randomly-rolled things that seem contradictory can be the most awesome I guess.

Quote from: Bloody Stupid Johnson;498722Thanks Clash
 
Thought it warranted a mention as one of the more interesting SF planets I've seen. I hadn't known the background, more proof of what they say about how randomly-rolled things that seem contradictory can be the most awesome I guess.

Thank you very much for mentioning it!

-clash

NP...anyway on to vehicles...
 

 
Above: Cadillacs & Dinosaurs vehicle card
 
 
 
Vehicles rules are critical in SF games where PCs are going to do battle in spaceships, and very handy in shipboard games. Mecha battle games (MechWarrior, Junk, Mekton Zeta, Robotech) have particularly detailed vehicle rules as well.
Other game rules that interlock with the Vehicles rules include Size, Gadgetry, movement rules/chase rules, cover (to passengers), and hit location (ships frequently get their own malfunction tables to determine e.g. if the bridge catches on fire or the crew on C Deck goes and sucks space – often even in games without hit location systems for characters). Important combat manuevers include Trample/Overrun and ramming.
 
Approaches to Vehicles: Vehicles rules at the simple level can include just a few sample vehicles with a cost for each and maybe some very basic data (the GM may be left to wing it on the details, as often as not); More complex rulesets may attempt to actually give rules to let players create their own vehicles, much more ambitious. Cost for vehicles is sometimes in game cash (credits or gold pieces) – though sometimes a vehicle instead has some sort of associated “character point cost” /counts as an advantage etc.
Some examples here to consider the sort of different approaches:
 
*Teenage Mutant Ninja Turtles has a perhaps surprisingly detailed DIY vehicle systems: these tend to be added to across sourcebooks with specifics added as appropriate (one has road vehicles, others space travel or time travel, etc). There are large price lists for common features, with prices arrived at by the designer either using real world costs or in an ad hoc fashion (a mixture, but I’m not entirely sure which). Here for example a PC might pay the price of a basic car or motorcycle (which gives them basic stats), then a cost to upgrade the electrics and add armour, weapons, radios, etc.
 
*the infamous GURPS Vehicles (we’ve all seen the motivational poster?) Calculus isn’t actually required, but it does go as far as using cubes/cube roots of volumes in some places. The entire design process is an abstraction of an engineering task, where a vehicle is built from scratch (instead of starting with a car or motorcycle or boat, as in TMNT you buy everything individually including wings, wheels, hulls, and turrets). “subassemblies” and other components are selected, volumes and weights are determined, and so on. (as in the real world, the cash cost of everything is determined near the end, where you go back and figure out you can’t afford to build the thing in the first place). Size modifiers and hit points are determined at the end from the total volume. It is a more flexible approach than TMNT, but more involved; the system is also very detailed e.g. gives you the costs of everything you might want from electrified rails to “contra-gravity generators”. The degree of detail in costing is a little odd given that Wealth level itself is quite abstractly determined by spending points, but this sort of cost system does perhaps help with setting questions like “how many aircraft carriers can Government X afford?”
 
*a power-based approach, as in DC Heroes or HERO. In these a vehicle is just an example of the gadgetry rules, which themselves use the powers systems. An item has a cost in character points, and is sort of built like a character (though it won't have the full range of attributes). In DC Heroes, every gadget at least has the Body (hit points) attribute, and a vehicle will also have either a DEX or some sort of propulsion Power, such as Flight or Running; custom items will cost points either paid initially to get the Gadget advantage, or by the creator during the building process if built during a game. Hit points and exact abilities are determined by specific advantages/disadvantages given to powers and how they are “skinned” as regards fluff.
 
Impact on Character Generation: In many games, characters may have the option to get driving/piloting skills of some sort – depending on how much focus of the game is on this, Pilot may itself be viable as a major archetype/class, or a few skills of this kind may just round out a character who is already something else in concept, like a super-spy or warrior. Shadowrun 1E has ‘ Rigger’ as a separate archetype but (realizing that what they do tends to occur separately to other PCs or be downplayed) eventually merged it with Decker. D&D 3.5 has various “charioteering” feats – which were not really worth picking up for PCs, but were possibly of interest to the GM if they wanted Gladiator-style drive-by scythings in their D&D arena game. The old Robotech game by Palladium, being largely about giant robots blowing up other giant robots, has specific classes for different vehicles, e.g. Veritech pilot or Destroid Pilot.
 
Other Notes
*Attribute sets for vehicles: Marvel Super Heroes limited vehicles to three stats: Control, Speed, and Body. DC Heroes builds as noted lets characters build whatever attributes or powers they feel like into Gadgets. Mecha games may provide a bonus or multiplier to the user’s own STR, or have an intrinsic STR score. Some games may have a percentage or other value for ‘reliability’ as a unique vehicle trait e.g. 2nd Ed. AD&D gives ships a “seaworthiness” rating, rolled to avoid sinking. Star Wars SAGA, IIRC, gives vehicles the same attributes as characters including e.g. Strength, Dex and Con.
 
*Damage and Scale: vehicles may use a larger scale of hit points than characters. Spelljammer (AD&D 2nd Ed) has “ship points” (1 SP = 10 HPs), while Palladium has Mega Damage (1 MDC = 100 SDC). West End Games Star Wars had, IIRC, 3 different scales for damage, IIRC, from personal to small vehicles to larger ships like the kilometres-long Super Star Destroyers. Metascape: Guild Space uses several scales. Savage Worlds has "heavy armour" - a heavily armoured thing (with this tag) can only be damaged by a "heavy weapon";  heavy weapons don't inherently do any extra damage to other objects though most will be rated fairly highly. The tag just prevents tanks being accidentally obliterated by crazy damage roll-ups from handguns or the like.
 
*Mounts in FRPGs are somewhat similar to vehicles in some ways, though they have statistics more like those of monsters, and may even level up automatically with characters to stay relevant.
 
Interesting ideas from other systems: Ork vehicles in the Warhammer 40K wargame used miniature vehicles for combats. In the older rules unlike other factions as many extra ork figures could be piled on as the player wanted, but any figures falling off were killed.

Falling: one of the more interesting methods for this is to base damage on the falling person or objects size; handy since big things usually have lots of HPs (you probably want a crashing shuttle to actually be totalled rather than scratched by 20d6 damage). While I'd normally feel damage proportional to size to be fine at least in a fantasy game, IRL the square-cube law (double the height = 8x the mass) means larger objects actually suffer worse from falling; compare effects of a 10ft fall on a flea and an elephant. ‘The Mutant Epoch’ was a recent game that allowed for this. Mechanics around this sort of thing typically become easier with a “Size score” for characters/objects, though Epoch used a table.
SF games may need to allow for differences in falling damage based on planet gravity. Detailed systems sometimes add modifiers for landing surface e.g “deep water” or “mud”, “snow” etc. (HarnMaster). Rolemaster used a table to determine falling damage, in keeping with how weapon damage also requires a table (RM falling damage is relatively dangerous due to speed with which bonus increased and inability to add most defensive bonuses).
Characters may sometimes have options to reduce falling damage: Palladium has a 'roll with Punch/Fall' combat move, while other games e.g. 3.x D&D let characters make Jump checks to mitigate damage.

Interesting note on increasing falling damage in Pathfinder 2.0 (PF having similar falling damage 2E/3E, but more hit points) and dungeon design:

QuoteBulmahn:- "I messed that up in the podcast, having misread the sentence in the rulebook. To be clear here folks, we are not going for super realistic physics here. This is an RPG after all, but it would be nice not to have to have pits in dungeons that are 50 feet deep just to deal reasonable damage to a character (it always messed up dungeon floor plans.. where are those pits going down into the level below).

Lifting Objects: depending on system this may be a totally fixed roll (i.e. STR x 10), a base from STR increased by some sort of Willpower roll (Storyteller adds Willpower successes, or possibly a STR check modified by another STR check (mostly I find this weird, though I suppose it makes a Strength scale slightly more exponential, or something). Depending on outcome a roll may be an effect-type roll (roll anytime you lift something, roll determines amount lifted; compare that to the weight) or in simpler systems weight determines check modifiers to a simple check e.g. HarnMaster will make a character roll under from [End x 1] to [End x 5] depending on how heavy a load is.
Some systems may apply separate adjustments for base Strength and Size to lifting objects e.g. 3.x D&D; Shadowrun 4E has an automatic base lift of [STRx15] then rolls [Str+Body] dice for extra successes (worth 15 kg each), giving a weird result that the variable only is affected by Body.
Skills rarely improve lifting (the Trinity and Aberrant games by White Wolf, for example, uses a dice pool of [Strength+ Might skill]; this replaced a more complicated system in e.g. Werewolf IIRC where base STR + Willpower successes were used on a table, complicated by Willpower having a 1-10 rather than 1-5 range but needing a lower weighting than STR. In the Str+Might system, Willpower could still influence this but only indirectly (as on all rolls), by spending a Willpower point.
 
Note that lifting capacity is proportional to muscle cross-section and roughly increases as the square of height, though realistically using this, giants aren’t going to be able to stand up (weight increases at the cube of height).
Another designer friend of mine who was once something of a body building enthusiast, once built a complex derived system for Strength; a character determined a final Strength using a base value from the square of their height, a Muscle score which reflected how much working out they had done (never rolled against directly, aside from 'bodybuilding contests'), and a separately purchased 'build' multiplier, which were all multiplied together to get a final strength.
 
Older D&D sometimes used a combined Strength total to shift an object ('30 or more to move the slab') which was unfortunately out of kilter with the exponential scaling of the attribute, and meant a titan (Str 25) couldn't move objects 3 ordinary humans could (see for instance 'Wall of Iron'). A more precise system was HERO's adding together of pound values to get total lift, which could then be mapped back to a STR score.
(Another 'ad hoc' system seen in one GM's Palladium game was to give a PC extra d30 rolls under Strength when NPCs helped move levers etc.- d30 being needed because of Palladium's stat scale, and the NPCs having lower and maybe not exactly known Strength).

Also see thread here for a not-completely-serious extended discussion on rock lifting in various systems:  Characters-from-Different-RPG-Systems-Try-To-Lift-A-Rock

Off-topic, another instance where multiple AD&D characters added together their Strength was the 2E Tome of Magic 'Champion's Strength' spell - this let several priests donate their strength damage modifiers to one target. So, a completely different ad-hoc mechanic to any other sort of Str assist; this one had the problem most characters have a +0 damage modifier, or this could give a damage bonus that's normally impossible from just Str (six titans could cast it for a +72 damage bonus).

Encumbrance: somewhat relatedly, systems may use exact encumberance in pounds; Basic D&D instead measured it in “cn” for coins, at the rather heavy 10 cn = 1 lb. A few systems (Swordbearer, reputedly; Dragon Warriors) also use just an “object limit” e.g. 10 objects, plus/minus possible Str modifiers. Of course games often handwave the details of encumbrance, particularly when PCs have horses/vehicles/bags of holding.
deadEarth uses weight but gives containers such as backpacks or hiking packs a negative weight (e.g. military backpack:-15 lbs), to reflect their ability to increase carrying capacity.
 
Fire: fire damage works particularly well for systems where its possible to calculate a probability or DC of something catching alight off a number of points of damage - though very few systems actually do this (see discussion of Marvel Super Hereos above under Combat – Damage). Fire (or sunlight for vampires, say) might also be surface area based, as below.
 
Immersion Damage (in something bad e.g. acid, lava): damage for this is logically based off amount of surface area exposed, as a proportion. The easiest way to handle proportions in game is in count success systems, by setting the target number i.e. if "Boiled in Acid" is 10 dice of damage, complete immersion would be TN 0 (= 10 damage) and half submerged would be TN 6 (average 5 points of damage).
 
Some systems have tried to have surface-area based calculations to deal damage - this only works well if a creature's HPs (or other attacked attribute) are at least proportional to its surface area. For example, the 5th level druid spell Slimewave in 3.0 D&D hits a creature with a patch of green slime for each 5ft of area it has, each of which deals d4 Con damage a round; an Orc (medium size) might survive for three or four rounds (one slime patch), while the spell dissolves Colossal creatures (like most great wyrm dragons; 40ft facing or 8 slime patches) within the round.
(While it was for weapons) Larger-than-man-size damage in AD&D (2nd Ed.) could cause similar less drastic problems for monster PCs: PCs belonging to races that normally had multiple monster HD got a bonus of only +1 HP per monster HD to a PCs normal class-based HP, making them relatively squishy. (a 1st PC fighter-ogre would have d10+4 (for 4 HD) + Con bonus HP (or 5-18), vs. a real ogre's 4d8 (4-32), but still take d12 longsword rather than d8, or 2d8 from a bastard sword).  
 
Luck Rolls: some games have a 'Fate roll' or 'Luck roll' that is a mostly unmodified, to use ad hoc to determine if something happens - examples include the fixed 5d10 roll of original Storyteller, and the (albeit unnecessarily complicated) d100-roll-under-another-d100 'Fate roll' in World of Synnibarr.
This is basically just a streamlining of how most other systems would ad-hoc assign percentages of whatever event happening ("there's a 40% chance the goblin storeroom has the iron spikes you need") that the DM opts not to decide just via fiat, though it also puts it into the context of the games' general resolution system and so gives an output (i.e. Number of Successes for Storyteller) which might be useful for game purposes in some way.
Additionally, using a single system lets the resolution chances be modified by other defined modifiers, such as how 'luck rolls' in Storyteller can be modified by the Charmed Existence merit (ignore a single "1" on any roll).
Sometimes this can give PCs a way to leverage greater-than-expected chances of success, if they can burn rerolls or Luck points or something on checks.

T&T luck rolls and BRP luck rolls are sort of similar too, though using a Luck attribute. For T&T this likewise can be used to get game-mechanically-useful effect, though it also means the Luck attribute either modifies everything (or is ignored perhaps inconsistently - a number of places in the solos use some other [unmodified] die roll instead - for instance having a character survive if they can roll doubles).
Whether something ends up as a 'luck roll' or a standard skill or attribute test depends a bit on the areas defined by other attributes in the system (attributes, resources ratings, popularity scores, etc.)- this mechanic gets used just for things where existing values don't really apply. A luck roll could also be used if another value which does cover the conceptual space is not really mechanically testable due to lack of a useful scale or a missing method for testing that value in the relevant situation (e.g. damage in many games, attributes in Palladium which doesn't have attribute checks per se), in which case its a minor break in the system.
4E D&Ds 'skill challenges' might also be used to resolve some tasks that otherwise need a 'luck roll' - sometimes useful, though potentially leading to shoehorning of skills into situations where they weren't really that applicable to.

Luck rolls might need to be in addition to a normal random determination, to avoid absurd results (e.g. discussed here in passing) - if a character with 25% luck is choosing one of three boxes at random, an unmodified Luck roll would give a 1-in-4 chance of the correct box. Consequently, game mechanically, you have the option of either a) making a luck roll an extra - if you pass the Luck roll, the correct box is automatically chosen, otherwise there's a 1-in-3 chance.  If every character by default has a Luck rating, this could generate too high a chance of the right box, however. Another approach is to modify the Luck check for the # boxes such that a normal 'luck' character has a 1-in-3 chance, a particularly unlucky character less and an unusually lucky character more.

A "luck" attribute can be used to do "saving rolls" as well as random event determination. Tunnels and Trolls often works that way; Low Fantasy Gaming has a Luck which works like a stat but allows level-increase (Lk = 10+1/2 level), with some checks also getting attribute modifiers e.g. Dex to dodge a Lightning bolt, and with the score reduced by 1 when a check is made. Characters also get a 'reroll pool' equal to level.

Cf. post #60 Event Generation
Making a 'luck roll' be an attribute test on a character's Luck attribute can also be thought to favour PCs, who usually have higher-than-normal attributes. As an example, Chill gives characters who are swimming more than 24 hours a Luck roll (on their d% Luck attribute) to find floating debris, or drown - having a game system for this gives a generous result, though at least it uses a game mechanic in such a way that a character's chances are fair.

Saving throws: older games tend to have fairly idiosyncratic systems for saves, with later systems streamlined them for easier identification of what does what e.g. Fortitude/Reflex/Will in 3.x D&D. Modifers may be class-based, or racially-based (e.g. in Battlelords of the 23rd Century). Some systems may just use skill checks or attribute checks for the equivalent of saves; RQ2 uses skills but with an optional rule for some of the equivalent skills e.g. Resilience that they be capped at [stat * 5], Tunnels & Trolls just uses attribute checks (older editions have no other numbers). There is a bit of a design advantage in separating "saving throws" as a distinct category in that it makes it easier to design effects that don't harm saves - for instance the "poisoned" effect in 5E disadvantages skills but not saves, so a character isn't hampered if they need to make a save to end the ongoing effect of the poison.

AD&D 2E was somewhat weird in that a save-like situation might use either an ability check (roll under d20) or save (roll over d20) which gave very very different results - the 1st level thief with an 18 Dex would be 90% likely to pass a Dex roll to not be crushed by a falling boulder, but would probably fail the equivalent save to dodge (i.e. a save vs. Breath Weapon of 16+, w/ +4 defensive adjustment from Dex).
 
A trend in design discussion recently seems to be toward rolled saves with standardized “defense” numbers like “Fortitude Defense”, an integrated system with armour class or the like. This isn't really a new idea: Hero for example has attack/defense values for both physical and mental combat, as does the 1992 Edition of Gamma World which used rolls of d20 + mutation modifier vs. “Mental Defense” (the mental equivalent of armour class). Dragon Warriors is similar, with hostile effects occurring if a roll is made under the attackers’ Magical Attack (just as a sword blow hits if it rolls under a warrior’s Attack).
 
This does make the system more consistent, and can be used to more easily reset an attack from one defense to another, but keep in mind the following, IMHO:
 
*Feel: an “attack” that lets the GM announce a “death” result feels less fair than getting a save to negate Death, even where the probability is identical. Dragon Warriors is particularly an offender here, since save or dies (SoDs) requiring a Magical Attack rolls are frequent – the actual text example of a Magical Attack is for a gorgon rolling to petrify a PC
 
*Area of Effect/multiple checks: a GM may be able to roll several saves for monsters faster than a player can roll several attacks, as they know the target number i.e. the GM quickly calculates he needs a 15+ on d20 to save vs the fireball and just rolls a bunch of dice, counting how many are crispied). This can however go either way, depending on whether its the players or the monsters that dish out the most AoE effects.
 
*Who rolls what can have interactions with other rules, like whether a character gets to spend luck points to reroll. An amalgamated defense system sometimes gives other odd effects, like invisibility giving a wizard +2 to hit with their sleep spell (4E D&D).
 
*Conflation: in a defense system there is a tendency that a secondary roll to resist gets streamlined out; instead of an attack vs. AC that deals X damage and then requires a roll vs. being moved, only one roll is made. That is, two effects that should be resisted separately (by different factors) end up conflated - ‘I hit the Gargantuan monster’ and ‘I push the Gargantuan monster’ are different things, but a single roll often seems to do both, ignoring most of a critter’s modifiers against half the effect.
 
An interesting compromise between rolled saves and standardized defences can be reached here using the idea of a ‘Passive Defense’ vs. ‘Active Defense’. For example in Talislanta or GURPS, a character receives a passive defense vs. physical attacks they’re normally aware of, but can opt to spend an action to make a full “active defense” against them (a dice roll) to raise the difficulty to hit them.

Final Note on Saves: Possibly more effort goes into designing saving throw systems in games where characters are expected to probably last a whole campaign - parallel scaling of attacker/defender adjustments, character abilities giving rerolls, carefully balanced effects, rerolls each round, etc.
T&T spells often don't allow even an ability check to resist; Gamma World characters don't exactly have a saving throw system - in most editions a 'Health check' system works against a handful of effects and 'mental defense' against some others, but things may also frequently end up outside those fairly limited subsystems - e.g. AoE damage is automatic although a character can 'duck for cover' for 1/2 damage with a Dex check at -5. GW characters normally convert to D&D (1E DMG, or Dragon #187) as not receiving saving throws vs. spells, also.

Insanity and Horror: Games noted for rules around these sorts of things include Call of Cthulhu (Sanity rating as a percentage, game lists various things causing SAN loss and loss of a number of SAN points will roll for random insanity), and Palladium (various random tables with type of roll indicated based on the trauma, as well as having "horror factor" rolls for supernatural creatures; characters receive just a save vs. insanity [adjusted for Mental Endurance] rather than tracking individual SAN points as in CoC). Kult also has insanity rules - based off insane characters being right and so giving powers to character with significant numbers of insanity points.

Starvation and Thirst: Games sometimes have rules for these depending on likelihood of this coming up. A Survival skill may be used to find food for X people for Y days. Starvation may deal fatigue damage or Str loss, or just damage; thirst may likewise cause fatigue or damage or CON loss. Dark Sun for 2E AD&D had thirst rules dealing around d6 Con damage/damage if a minimum ingestion amount (based on race) was not met, as well as having rules for "Severe Desperation" which could cause a character to become chaotic evil to obtain water if they failed a saving throw. CON damage from dehydration was a bad way to go in that it notes specifically a 0 Con character had only a 25% resurrection survival percentage, i.e. they use the 0 Con rather than their normal Con for resurrection. This was somewhat WTF in that a character who was a bit desiccated would be probably irrecoverable, while a character killed with an axe to the face and then over time reduced to a clean-picked skeleton would roll for resurrection at no penalty.

Item breakage, miscellaneous wear and tear and consequences : games vary in how much they want to handle 'gritty' realism in the 'Fantasy Vietnam' style. Games can have assorted rules for item breakage, item saving throws, and miscellaneous consequences. Early generation games generally work through a detailed, procedurally-generated system where lots of specific rules are invoked - a saving throw fail vs. fireball may trigger a bunch of secondary item saving throws, a spell mishap may involve a roll on the spell mishaps table, arrows are tracked individually, a shield might have a number of hit points that are being crossed off as its used. OTOH, in more recent games gritty realism could be handled more abstractly - Dungeon World for example builds in assorted losses as consequences of failed 'moves' where rather than having a separate roll, a limited success on a save/attack/whatever can generate item losses, running out of arrows or whatever.
On the plus side, this saves a lot of detailed book keeping. It does introduce possibly more GM fiat into results, and players may have less leverage to avoid potential negative consequences. If a partial success lets the GM do a dick move, then a player strategy to avoid something most likely means they get a different negative consequence rather than avoiding it entirely - chaining your sword to you to prevent it being disarmed prevents a 'drop weapon' being narratively feasible, so some sort of fumble might break it instead. Or a donkey loaded with bonus arrows might just prevent someone choosing the 'runs out of arrows' partial success Volley option, rather than being an advantage.

Above: the Blind Warrior Women are OK with Rifts not having Spot checks.
 
Noticing things in games typically uses a mix of player-driven description and rolls to notice things for tricky /in doubt situations. Perception scores may be rolled or function as some sort of target number (“Passive perception”). This is already touched on a bit in the earlier post on cutting down excessive dice rolling.
Passive perception may also be desirable in that the player is not called on to 'make a Spot check', and hence isn't provided ooc information that there is something there. Some GMs may roll player rolls unknown to them in secret, ask for a dice roll without saying which modifier applies. It would also be possible for a game with a 'wild die' /die pool /multiple checks to have the GM roll some of the dice, giving the player only partial information on how successful a roll was. A particularly cruel approach I've seen suggested is to have 'botches' stored by the GM - they can use it for the event its rolled for, or they can keep it and spoil another roll later with misinformation - meaning that no roll results are entirely knowable.

AD&D is interesting here in that while some specific situations such as “Hear noise” or finding secret doors are individually defined, it typically uses player described searching (“I look in the pocket of the cloak”, “I see if I can lift up the bottom of the chest”, etc). No general perception attribute though specific checks could cover for it when appropriate e.g. ability checks. Palladium is similar to this as well, though one game (Nightbane, aka Nightspawn) adds Perception rules.
 
Other games may have Perception attributes (/skills/derived attributes), though this can in rare cases cause more confusion than not having them; while additive systems may just use an opposed roll, roll-under mechanics can struggle with this. Jonathan Tweet discusses this in his notes on how Runequest influenced the structure of the d20 system here; http://www.jonathantweet.com/jotgamerunequest.html
(Anecdotally, I’ve found this myself not too long ago. In Cadillacs & Dinosaurs, a d10 roll-under system, we had a situation where the Observation skill had a default of zero for untrained characters regardless of attribute – a rule that easy tasks get a x2 skill multiplier wasn’t helping); this was particularly odd when someone else failed a Stealth check, requiring some pondering - requiring a roll by PCs to notice hiding NPCs means the PCs probably fail to notice them; requiring a roll by NPCs to sneak means the NPCs probably fail to sneak.).
 
Dirk Remmeke here discusses the idea of not having a specific perception skill (or attribute) with the relevant skill instead being highly situation-depended

Other perception related rules:
HERO has detailed rules that distinguish between “targeting” and “non-targeting” senses; characters can have senses beyond the usual few that count as ‘targeting’ (equal to vision) and upgrade a “non-targeting” sense to “targeting” (i.e. Daredevil radar hearing).
Some games have multiple vision types:
*AD&D has “infravision” –allowing characters to see using heat radiation – and more rarely “ultravision” which used ultraviolet radiation assumed to be common in the underdark (?), and provided vision similar to normal vision, rather than Predatorvision.
*Palladium had “night vision” (seeing in low light conditions); D&D 3.x distinguishes between “low light” vision which works as long as some light is present, and “darkvision” which just breaks the rules of physics, as well as defining "blindsight" and "blindsense".
*5E D&D makes darkvision more generally available than 3E (replacing low-light) but it is somewhat weaker than 3E darkvision and includes some of aspects of low-light vision; instead of the only limitation being that colour discrimination is lost, 5E darkvision gives vision equivalent to 'dim light' in total darkness, i.e. lightly obscured, i.e. disadvantage to perception checks/-5 to passive perception, and full vision in dim light.
*Shadowrun has both Low-Light and Thermographic vision.
*Dragon Warriors distinguishes four types of sight: normal vision, darkvision, gloomsight, elfsight, and panoptical vision. Creatures with darkvision (orcs for example) could see perfectly well in utter darkness but were blinded by bright daylight (the same penalty humans had in the dark). Creatures with gloomsight, such as dwarves, preferred shadowy places and had a lesser penalty in either daylight or total darkness. Creatures with elfsight preferred light but had lower penalties in low-light conditions, while creatures with Panoptical vision were comfortable with any level of illumination (no bonus or penalty, which in DW still gave them lower perception that a day creature in bright light, which had a bonus).
I reverse-engineered DW-type vision back into a powers system for one of my games based off Marvel Super Heroes/FASERIP, which I'd dubbed Unearthly Heroes.  It had a darkvision system which was an extension of the basic powers system. Powers and attributes both used the same universal rating system - 0 (nonexistent), 2 (feeble), 5 (poor), 10 (typical), 15 (good), 20 (excellent), etc. The "Enhance" power added its rating to another power or attribute, up to x2 base unless the 'unlimited assist' advantage was added to it. Light was also given a rating (as the 'Light Generation' power) with 10 (typical) being dim light, 15 good and 20 full daylight, and penalties for very bright light (30/remarkable or better). Darkvision simply worked as Enhance operating on the environment's "light generation" rating. 'Unlimited Assist' was needed to see in pitch blackness (light 0); and the 'Always On' disadvantage could make already bright light blinding, i.e. as seen for drow or other light-sensitive creatures.
*Recon has a table of light condition x precipitation level to determine maximum effective range, with another line on the chart setting maximum for heavy/light vegetation). See below:

(note the die roll for precipitation level. Could also be an example of 'grid rolling' if the GM rolls lunar phase too.)

Lessons in Hiding
Some further notes on stealth.
AD&D: is interesting in having scores for both 'hide in shadows' and 'move silently'. Description of how these worked had some vagueness - notably some GMs might rule both checks required and necessary (making stealth nearly impossible at low levels) while others used 'hide' as a second save when 'move silently' failed - for ducking for cover. There is also some debate on how to run 'untrained' checks (one interesting solution being to use 'surprise' to represent an opportunity not just to get free attacks but to sneak past).
Savage Worlds: gives two checks in most cases - normal guards move to high-alert after one roll is failed, and notice targets after two failures.
Burning Wheel: stealth is particularly called out for its 'Let It Ride' rule, where multiple checks aren't required unless circumstances change.
(Miniatures-based) The Fantasy Trip suggests removing invisible creatures from the board while they're hidden.

Overall: stealth varies between games along two axes: how difficult it is to hide and how much advantage an 'alpha strike' provides (this last depending on average hit points, bonus damage for sneak attacks, etc).

Finding items: this is not an RPG as such but a boardgame, but "Dark Darker Darkest" has a search system where characters roll dice = # characters, with successes indicating number of items found. Once successfully searched a room can't be searched again, meaning that a 5-person search party might find 5 things, while a single person finds only one thing and then 'exhausts' the room.

A few systems don't have any sort of crafting system. Others have skills for this, but without much development of how these are used – it remains up to GM discretion.
The normal ‘default’ system is probably making a simple skill check to construct an item, with roll determining final quality, using time and cost guidelines depending on the sort of item. Fumbles or bad results may generate a setback or ruin a product completely.
 
Interesting crafting systems include:
*The D&D 3.x system uses a generalized Craft system; there are many Craft skills (as many as you care to invent) which share a single generic item-building system; this was an attempt to compress what were dozens of Non Weapon Proficiencies in 2nd Ed. D&D into a single skill. Instead of detailed tables of items with time to craft, difficulty, and cost, the system derives crafting time from item cost; the base cost of an item is 1/3 the final cost in raw materials, and a Craft check generates progress in silver pieces per week; this may work for estimating a craftsman’s income, but crafting an item may require a number of checks. Math is fairly cumbersome here since progress on an item in silver pieces is calculated as [DC x roll]; item quality is fixed (a character can fail to make a thingy in the allotted time, but can’t turn out a crude item or a masterwork item accidentally. The generic time means that some items take a long time to craft and makes e.g. goldsmithing much lengthier process than iron working.
 
*Warhammer 2nd ed has skills for crafting but doesn’t explain how they work; they are rolled together even more than D&D3, with craft and “profession” type skills both grouped into the skill “Trade”.
 
*Shadowrun; in 1st edition a Craft check determines how long a task takes; divide the base time by the # successes. Time required to build an item is based off cost but with divisor varying by type of item. By 4th edition, Build/Repair evolved into an extended test (rolling and accumulating successes across several rolls).
 
*Alternity uses simple checks for Juryrig (temporary repair), but complex skill checks (Bill Slavicsek’s first attempt at Skill Challenges) for the Repair skill or to build items. Characters can score multiple “successes” for good rolls, up to 3 per attempt (a d20 roll under their full skill score is worth 1 success, under half score is worth 2, and one-quarter of the score is worth three successes; 3 failures or 1 critical failure botches the challenge) and up to 10+ may be needed depending on repair complexity.
 
*In most systems each die roll for Crafting (success or failure) takes a certain amount of time, but Burning Wheel varies this. It uses a count-successes system; proportion of necessary successes determines what happens:
0% - an apparently magnificent work [125% usual time required to create] that crumbles to junk when first used;
Under 50% - junk produced, in half the base time (throw it away)
50%: junk produced, in quarter of the base time (throw it away).
One less than needed: item that looks serviceable but fails “dramatically” at some point.
 
*HarnMaster crafts have a weird effect system, mostly demonstrating an interesting workaround to limitations of the core mechanic. Harn has some difficulty determining how well a character succeeds at a task; it does not use "margin of success" to determine how well a character succeeds, instead speeding up results in combat, etc. by having any roll ending in an 0 or 5 (an 05,10,15,20, etc...) be a critical success or critical failure.
Crafting uses the same system, but to go back and generate more detailed results for Crafting (i.e. higher quality items for more skilled craftspeople), it uses a "Value Enhancement table" and a "Product Quality table" which cross-reference a Skill Index (the 10s place of character skill) with a Critical Success, Normal Success, Normal Fail or Critical Fail result to give a final value or product quality. This gives slightly odd results in that (for example) a character with 60% skill (SI 6) can generate either a x4.0 (Critical Success), x2.0 (Marginal Success) or x1.0 (Marginal Failure) value enhancement, but not a 3.0.
The product quality table is similarly quirky; range of modifiers makes it quite difficult to forge a product of average (+0) quality.
 
*Gamma World 4th Ed (1992) has very few skills – despite my describing it as a ‘derived attribute game, each class has 3-5 unique skills - but technical skills are strongly represented, with one of only 4 classes, the Examiner dealing with ancient artifacts and getting separate skills in Jury-Rig (=building items from scrap) and Repair Artifact. The warrior class, Enforcer, also has a “Makeshift Weapons/Armour’ skill (one of their three skills). All characters also have a “Use Artifacts” derived attribute; this is used on a trippy flowchart with random rolls to determine if a character can determine what an item does, or ends up eventually at results including ‘Dangerous Event’, ‘False Function’, ‘Falls Apart’, ‘Assumed Useless’ and ‘Assumed Broken’)..
 
*GURPS is noteworthy for usually having a number of separate variants of a Craft skill, by Tech Level.
(Palladium tends to do something similar but less systematically - it would just ad hoc define separate e.g. blacksmithing, flint chipping etc. - Transdimensional TMNT has a number of such 'historical' skills). DC Heroes assumes modern tech and 'gadgets' are built using that tech level, except that a "Genius" advantage lets characters construct more advanced items (robots, force fields, etc.) (perhaps an example of something that would be better off as a skill modifier adjusting skill 'factor cost').
 
Exotic materials: Talislanta has weird materials including various colours of Adamant (alloys of steel and diamond of the appropriate colour); D&D has adamantine and mithril, as well as dragonhide, chitin, ironwood and obdurium; Shadowrun has orichalcum. One of the lengthier lists (I’ve seen anyway) is the exotic materials list of SenZar; each has its own special abilities, as well as an affinity for particular magics which reduce cost to enchant them (e.g. Supremium can receive the Bifurcation enchantment – x3 damage, deathblow cuts foe in half - at 10% of the normal cost).
 
Below: list of exotic weapon and armour materials and their properties from the SenZar RPG. (Arrangement of these into a periodic table is just me dicking around, not actual SenZar rules).
 


A variant of rolling a Craft roll every so often (such as 1/day) might be to roll one Craft check to see how long it takes to build something. Making it a time roll probably gets rid of the chance of a 'raw materials broken' result, unless that happens on a critical failure: another option would be to add a per-day cost such that a low roll does cost more (abstractly representing the likelihood that a long time in Crafting will involve starting again with more raw materials). This works a bit differently in that the worst-case Craft result could be set at [cost = over the counter cost] such that a low skill point investment in Craft is still useful instead of being worse than no Craft skill.

“In the land of Mordor, in the fires of Mount Doom, the Dark Lord Sauron forged in secret a master ring, to control all others. And into this Ring, he poured his cruelty, his malice and his will to dominate all life.”
 
I was initially going to separate Crafting into just magical/non-magical, but while thinking this over realized that since some games have technological item building rules I should mention as well, so this would be something of a misgnomer.
 
Complex crafting may use similar rules to regular crafting, though class-based systems often relegate magic item building to particular classes rather than using skills.
 
Some interesting systems, in no particular order:
 
*1e/2e AD&D magical item construction is performed by wizards, and requires the GM to determine a list of fantastical ingredients – monster body parts and the like – which the wizard must quest for, hire adventurers to get, or buy through contacts (if available). Construction requires steps including the Enchant Item spell (6th level), a saving throw for the target item, casting of other spells (possibly requiring spell research), a Permanentcy spell (8th level, 5% chance of Constitution loss), and finally a percentage roll to see if the item works properly or is cursed. The wizard earns XP for constructing the item. Costs and processes for making an item are wholly DM-determined (though the monster manual often notes certain monsters are useful for certain things); magical items should be very rare (probably much rarer than they actually end up being in D&D games).
2E has a system of 'impossible ingredients' where a character might need to find/interpret what to get to serve as 'the breath of a mountain' or 'the shadow of a cloud' (based on Viking sagas?)- the Complete Wizard Handbook has a random table to generate these.
 
*Palladium Fantasy has most items constructed by NPCs called Alchemists. This again requires fantastic ingredients, but both items and ingredients have defined costs, and are bought/traded freely.
 
*D&D 3.x requires large gold expenditure to make an item (what this buys is undefined), as well as XP (representing “life force” of the caster). Items are in theory costed based on either [bonus-squared] or a spell level of an equivalent spell [e.g. spell level x caster level x 2000 GP], though standard items rarely follow the equation, and just have a listed construction cost and spells needed to create them. The right Feat and a minimum caster level is required to create items. Items require 1 day per 1000 GP to construct.
Broken magic items can be reforged at 1/2 cost, in a nod to fantasy literature.
 
*GURPS Magic uses estimated wages of mages to calculate GP value of magical items: a wizard can generate a point of magic per day and earns $700 a month (22 working days), so items cost $33 per point after factoring in about a 5% error rate.

*DC Heroes (3e): both technological and magical items are constructed by making checks of Gadgetry or Occultism skill vs. the number of points of the desired superpower to install this into an item. Characters must make a Resources check to buy parts, then someone (any other concerned party will do, not necessarily the builder) must spend Hero Points to actually construct an item, with a cost based on the strength of the power. Characters may get bonuses on the design by having Plans of devices (reduces task difficulty) – an interesting possible adventure hook.
DC Heroes gadgetry has been described as “resembling a Pentagon procurement scandal” (http://www.allenvarney.com/rev_02.html ); though note that (in 3rd ed. at least) Hero Point cost to build a device is much lower (perhaps a fifth or so) of adding equivalent Powers innately from Character Growth. Taking the Gadgetry advantage to initially own a Gadget is however a bad idea (same cost as just buying the powers built in, initially) unless the character has the Intensive Training advantage, which raises the cost to buy powers but cheapens skills.
 
*HERO purchases devices in character points, handwaving any construction or acquisition process; points are paid by the user of an item, rather than the builder (unlike in DC, you can’t beat up Batman and just use all his stuff without paying the points). Items use standard power costs, discounted by the Focus limitation to account for the possibility to removing them, and possibly other appropriate Limitations.
Savage Worlds is similar in approach to this – a character with “Weird Science” gets a new Gadget by taking the “New Power” Edge (using an item requires a “Weird Science” roll, but I’m otherwise unclear on whether you can beat up mad scientists and take their stuff).
 
 
*Tinker gnomes (1st ed. AD&D Dragonlance Adventures): a table of effects gives a base “Complexity” of an item; this also equals its base Size, except points can be exchanged between the two (i.e. making it larger makes it less complex). Exact component lists are provided including pulleys, gears, bellows, tuning forks, etc, though are mostly flavour; an item has components equal to its complexity, and base cost for each is multiplied x item Size. Build time uses a table and is based on [Size x Complexity]. Complexity score is compared to character level to see what penalty the device has to operate (to hit and damage if applicable; also, to a roll on a chart to see if it functions when used), while Size just makes the things unwieldy – gnomish inventions are often the size of a wagon and possibly as large as a mountain. A table of malfunctions is included for when an “unpredictable effect” is rolled.
The system is fairly workable (some specific effects are unbalanced) with enough flavour for the GM to make ad hoc judgments if needed.
 
*For magic items, GURPS has some sort of system of “energy points” and skill checks. Wizards can churn out lots of magical items given enough time, and occasionally can build items on the spot (I did like this feature - again something I've seen before in fantasy literature).
SenZar is similar to GURPs (but probably more broken); magic items have a Power Point cost and require time to make and Power rolls, but have only minor GP cost. A market value is given for finished items.
 
*2nd Ed AD&D psionics allowed for psionic item creation using the Empower metapsionic power; using this to create an intelligent psionic item requires only an freshly made item worth 250% to 500% of a normal item’s cost, and to pass a few power checks/spend power points, though the power takes days to use, usually fails (roll under Wis-12), and is expensive in terms of power points. The power did have a prerequisite level of 10th, and knowing it required power choices be spent to access the discipline, buy the power and prerequisite powers); still, this power lets you create intelligent warhammers that can disintegrate people for a cost of 10 GP. Items can also be given multiple powers.
 
*Ars Magica: interesting in that it has a currency for magic other than gold or character points, a form of magical energy called vis which is expended when constructing an item. Making an item requires a season in the lab; however, extended downtime is quite expected in Ars Magica.

*New Khazan (a sort of spelljammer for Tunnels and Trolls) has a sort-of-interesting magitech based around the spell points in 7E T&T ("Kremm" energy).

*I'm not overly familiar with Shadowrun 5E, but comments on one review I'd seen mentioned that it has rules for creating foci/items that make it difficult to make low-powered items - the creator's dice are limited by item Force (e.g. 1), rolled against 4-7 dice or so based on what the item does and needing a success for the item to be created.

Edit: adding this link to a quite interesting homebrew 'Magitech' system - spellcasting system designed to be heavily abuseable out of combat
http://www.giantitp.com/forums/showthread.php?t=252794

Lovin' this thread. That is all.

(Okay, not quite. I'm shocked, shocked I tells ya, that Torg's Drama Deck isn't even mentioned in the cards section. The omission is criminal, criminal I tells ya.)