Spinning this off from another thread, I thought it might be fun to come up with a  selection of magic items and gear (including armour, mounts, familiars, and clothing) that are a bit more unique. Not necessary "useless", but ones that don't provide combat bonuses or superpowers. Magic items that are, technically, magic, even if what they do either has no practical benefit, or the benefit is so limited and specific that this is the type of item that would end up in the $1 bargain bin of those 4th edition magic item shops in games where there is an assumed "magic item economy".

Examples from the other thread include:

The Hat of the Octopus: once a day randomly sprays ink d6 feet
The Magic Horse: poops apples and other assorted fruits. You could eat them, but most people don't want to.
Angler Fish Hat: When in social situations, the protrusion at the top of the hat vibrates, causing all characters of the opposite gender within 3d6 feet to pass a Wisdom test or they must bring the bearer some food.

I'll be adding to this thread as the whim takes me, please feel free to do the same.

Cape of Garnishment: this luxurious cloak is covered in iridescent fish scales and hemmed with marmot fur.

Every thing the character eats while wearing it tastes salty.

Boots l'Esprit d'Escalier: Allow the wearer to walk backwards at twice their normal speed. When they do so, the last thing they said to anyone within the previous ten minutes will be immediately forgotten by that person.

Sword of Herman the Iron - A +1 magical sword, +3 when fighting against an opponent in a duel. Whoever carries it, even in scabbard, must pass a difficult Wisdom test or automatically accepts any duel.

Sword of Pedantry: Anyone carrying this sword in its scabbard must correct any errors or mistruths spoken aloud in their presence or lose d6 HPs. If the sword is unsheathed, the wielder's AC is improved by +3, but they may not make any attacks until they prove their opponent wrong in a rhetorical debate. Their attack receives a +1 To Hit for every logical fallacy voiced by their opponent.

Actual items from my book.

The Eversharp Knife: A standard serrated eating knife that never gets dull. Can function as a dagger.

The Everclean Plates: Self clean after one hour of non-use. Make sure to get your leftovers off before that. No effect on anything still alive. Also a set of Everclean eating utensils.

The Everpure Bottle: Kills all bacteria in any liquid placed in it. Also prevents spoiling.

The Everfresh Container: Food placed in it never spoils or goes bad. Come in various sizes. No effect on non-food items.

The Everdead Coffin: Prevents a body placed in it from decaying or being animated. This one had an unexpected side effect of rendering dormant any undead placed in it. No effect on the Well Preserved though...

All of these were made by an adventuring necromancer named Everrest who was quite fastidious for someone who worked with animated dead and undead as a job description. Opened up a shop and sold his creations there so there are sets in the hands of more than a few individuals now. Death made him an offer in the end to continue crafting his household items in the afterlife. Also made the Eversoft Sheets for ghosts. Probably one of the most well known necromancers on the planet.

The Fowl Belt : Made from the skin of a mallard, and adorned with a clasp crafted from bill, the Fowl Belt will cause the wearer to quack incessantly for 3d12 seconds any time they fail a Charisma test.

Bugman's Lamp of Arbitrary Reminiscence: A small tin lamp made for attaching to the top of a crooked walking stick. When a candle is placed inside and lit, the lamp projects static images of the life of the tree used to make the walking stick.

Thunder Slippers: Small, pink, fuzzy slippers with felt bunny ears on the tips. When worn, all noise made by the wearer is increased by x d100 decibels.

Dragging Bracer - A metal armband decorated with an interlocking pattern of shiny black and white "U" shapes. Once per day the armband will allow the wearer to cast Telekinesis, but with the following restrictions: it only works on objects, has a limit of 500 pounds and can only move objects closer to the wearer, not away or sideways (a mid-air hold is fine).

Rhino Helm - Requires attunement. A brass helm shaped like a stylized rhino's head with no eyes, its jagged upper lip forming a visor. When wearing this you gain the benefits of the Charger feat if you don't already have it. If you already have the Charger feat, you gain the Mobile feat instead.  

In addition to these effects, the helm also allows you to use the Passwall spell once per day with the following limitations: The opening cannot be more than 5 feet deep, it lasts only 10 minutes, and requires you to slam your head against the surface you wish to affect (this doesn't damage you).

Conch of Nostalgia - A golden sea conch with a ring-shaped switch around its tip. When the ring is "switched" on, the conch produces a combination of bittersweet harp music and the sound of gently rolling waves. Those who listen to it feel somewhat sad for their lost childhood at the shore... even if they never had a childhood at the shore.

Moistloaf Carver: When drawn across empty air in a deliberate slicing motion, this perpetually dull carving knife will produce a slice of a grey-pink glistening substance that when eaten will sustain a humanoid for a day, albeit with considerable digestive distress.

Beasts will not eat the product of the Moistloaf Carver, and any humanoid with dietary restrictions or allergies will likewise find the slices intolerable.

Box of Reveries - This tiny box is studded with flakes of pink stone and contains a single pill. Anyone who willingly eats the pill sinks into a vivid lucid dream for 15 minutes. While the details of the dream vary with each user, they are always pleasant and idyllic.

The box will generate exactly one pill every 24 hours as long as the previous one was eaten or destroyed. Anyone who takes seven such pills in daily succession sinks into the lucid dream permanently, requiring a spell to deliver them before they starve to death.

As you can imagine, the box is often found in the possession of an emaciated but serene-looking corpse.

Jar of Jurons - This small earthen jar is sculpted with the face of the most smack-able little brat you can imagine.

If the jar's lid is lifted, anyone who swears or uses "dirty" language within 10 feet of it has that word or idiom sucked out of their vocabulary. From then on, any attempt to say the word or idiom will instead result in realistic donkey's braying.

The jar is uncanny in its ability to recognize swearing in any language or region. Its powers can never interfere with spellcasting however.

The effects can be removed with suitable magic or by smashing the jar. If the jar is broken it produces an hour-long swear-word filled tirade that drifts around like a cloud of noise before dissipating.