As simple as that, which games/systems use regular playing cards, whether wholly or in part? Can be just for specific subsystems, like chargen or magic (I'm aware of Deadlands, for example, one magic system in-game uses building a poker hand).

Any that do it in particularly interesting ways, or that work particularly well?

Crimson Cutlass

Crimson Cutlass is a pirate RPG that uses a Tarot deck and D8s (pieces of eight). The use of the Tarot represents Fate and neither the players nor GM can usually affect the Tarot. Instead, your job is to respond and react to the Fate. There's where the D8s kick in.

Except for personal duels, Crimson Cutlass uses Tarot to determine what happens in combat, incorporating both the Fog of War and the crazy confusion of sword clashes and pistol shots. As a player, you choose your PC's stance in the combat round (retreating, leadership of men, aggressive, outlandish, etc), but Fate presents what's occurs next and then your skills and dice lead to your success or failure.

In actual play, Crimson Cutlass is magic. It's easily the best "Hollywood Historical" pirate RPG I've ever played and its a shame the company folded in the 90s. It exists as a DriveThruRPG PDF now and I wish the company BETTER GAMES would do a Kickstarter or POD option to get the game back out in the wild.

However, as for RPGs using a regular deck of cards, I've worked on a couple. For whatever reason, I never could get them to work in a satisfactory manner. AKA, why I am drawing cards instead of rolling a die?

The best use of regular cards that I've seen in a RPG is Savage Worlds for initiative. It's a very fast, simple, quick and dirty idea that works fine at the table. Every unit / PC / major NPC gets a random card. Some special abilities give you 2 cards. Either way, the initiative round counts down from Aces to 2 and you go when you reveal your card. I've had some issues with the concept over the years, but in actual play, it just works to keep the "fast and furious fun" going.

Tokyo Nova uses playing cards, if you're into the untranslated Japanese TTRPG scene.

Quote from: Kiero;1101810As simple as that, which games/systems use regular playing cards, whether wholly or in part? Can be just for specific subsystems, like chargen or magic (I'm aware of Deadlands, for example, one magic system in-game uses building a poker hand).

The most obvious one is Castle Falkenstein (from R. Talsorian). Regular cards are used in all of the resolution, in about 3 ways that I'm remembering:

The main resolution method is that various skills or endeavors are associated with a card suit (Hearts for Emotional/Romantic, Diamonds for Intellectual, Clubs for Physical, Spades for Social/Status), and a card's rank is added to a character's skill to hit a target number, with cards not of the proper suit only worth 1. You have a hand of 4 cards (I seem to remember), that gets topped back up every round. One of the common criticisms of this resolution system boils down to "Why not play all of the cards in your hand every round?" By default, there really isn't a reason, aside from maybe "I plan to use another skill next round and wanna save this perfect card for it." You can house-rule fixes like "Your hand only regenerates at 1 card/round" if it bothers, though.

The magic system uses a separate deck in a somewhat similar way. Here, spells have "Harmonics" (Hearts for Emotional/Mental magics, Diamonds for Physical magics/Alchemy/etc., Spades for Spiritual, Clubs for Elemental), and each spell has a magic point cost in one of these categories (modified by a character's Sorcery rating, variables in the spell's range & other factors, etc.) When casting a spell, the Sorcerer must accumulate enough points of magic to fuel the spell. This is done by drawing a card blindly off the top of the Sorcery deck. If the card drawn is of the proper suit, it's value is added straight up as magic points. If a card drawn is not of the proper suit, it may be used anyways at a value of 1 (same as regular skill use), but it will have introduced harmonics to the magic, adding some wild side effect to the spell based on which harmonic is strongest (has the highest card rating). So a spell that summons a Spirit (Spades) that has a strong harmonic of Diamonds (because the caster used a card of Diamonds to add 1 to the total magic accumulation), might see the summoned spirit physically manifest in some way, doors wildly open & close, etc. A Sorcerer can choose to reject the cards that don't fit with the spell's type, but each draw off the Sorcery desk represents about 2 minutes of time in the game, so... it's a time trade off.

The 3rd way I remember the cards being used is as part of the Fencing system. In that system, each fencer takes 6 cards: 2 red, 2 black & either 2 jokers or 2 face cards of the same type. Red cards represent Attacks, Black cards represent Defense, Face/Joker cards represent Rests. Fencing takes place in rounds that consist of 3 Exchanges/Round. Each Exchange, the Fencers choose 2 cards, and there is a table that shows the results of the various combinations. Less skilled Fencers are required to take more Rests per round than more skilled Fencers.

Anyways, that's Castle Falkenstein. I'm OK with its core resolution, but I don't consider it great. I do really like the way Magic works with it though. It is entertainingly unpredictable and has some gambling trade-off on the decision to accept harmonics or not.

Savage Worlds uses playing cards for initiative and the chase sub system.

The SAGA Machine is an OGL game from Tab Creations. The basics of the mechanic and details about their various games can be found here -->  https://www.tabcreations.com/

Two-Fisted Tales uses both D10s and standard playing cards for its pulp action. The cards generally add boosts and resistance, but can also be used to gain clues.

Guardians of Order's "Heaven & Earth." Tri-Stat base, card-driven.

Talisman Studios' "Suzerain." a core system.

Pinnacle's "Dealdlands." 1e ~ 2e?

GDW's House System.

Lace & Steel used either Tarot cards or regular playing cards.

There are 3 or 4 obscure older one offs out there. But I'd have to dig to find them.

Quote from: trechriron;1101849The SAGA Machine is an OGL game from Tab Creations. The basics of the mechanic and details about their various games can be found here -->  https://www.tabcreations.com/

Someone retrocloned and OGLed the SAGA Rules System (Dragonlance: Fifth Age, Marvel Super Heroes 1998)? How did I not know about this?!

Quote from: Omega;1101858Lace & Steel used either Tarot cards or regular playing cards.

If I remember correctly, this uses special cards.

Torg Eternity and Torg Classic used the Drama deck.

Quote from: sureshot;1101889Torg Eternity and Torg Classic used the Drama deck.

As well as the derivative Masterbook system games, like WEG Indiana Jones.

Quote from: Alexander Kalinowski;1101892As well as the derivative Masterbook system games, like WEG Indiana Jones.

But again, I'm pretty sure the original poster was just asking about regular playing cards, not custom cards.