This is so mean, I can just imagine a card being written for this that is extremely long and only in the last sentence does it say “requires attunement”
Implement it as you wish. I currently flip a coin at the start of each day, and depending of that, it's good or back luck for the day. Never communicate which, let the player using the ring find out.
Something with a very niche useage like a Wand of Ring Detection; starts with 4 charges and regains 1d4 charges at dawn, expend a charge to become aware of any and all rings within 30ft.
Would usually be useless, until the one time you can use it to recover a lost/stolen ring or become aware of someone hiding their powerful magic item!
Or when they start using it at random and become aware of random little trivia of NPCs around them!
Also, chain mail would be obnoxious to someone using the wand!
Glasses of Magic Sight
While looking through the glasses, a faint aura appears in the presence of magic within 30 feet, akin to the Detect Magic spell (no action required).
You also have disadvantage on Perseption checks and Investigation checks while looking through the glasses as the magical aura of the Glasses of Magic Sight obscure your vision.
Side note: This is more or less a simplified version / original intent of a Magic item in a game I'm playing in. Though as of now in that game it works through activation (i think, and its probably an action like Detect Magic) but as it is a prototype on each activation the user needs to roll a d10(?) to see what happens out of the following things (can't remember the exact odds for each, also probably forgotten a couple effects)
Nothing happens
Activates as expected
The aura emitted from magical sources is blindingly bright
The glasses help you see Magical things by making anything that's not magical invisible to you
Squirrel sized, slimy creatures that infest pocket dimensions like bags of holding. They eat rations stored in them and occasionally weird you out by leaving a mucusey trail across your hand as you're digging around.
Ring of invisibility. Doesn't grant the wearer invisibility, it's just invisible. If encountered in a shop the shopkeeper will be unable to find where they left it.
@subtext Something I've used in a handful of campaigns. is the "Deck of Many Answers".
It appears as a deck of blank faced tarot sized cards. If discarded, the card vanishes and returns to the deck.
If a player asks a question before drawing a card, the card contains a hand drawn sketch attempting to illustrate the answer to the inquiry, but never with text or numbers. However, the deck is not omniscient and it's answers getting increasingly symbolic and open to interpretation the more abstract or game breaking; the players inquire.
Usually found by players, with no instructions.
Figuring out the shtick usually provides a lot fun, and they end up being MILDLY useful should players get the hang of them.
Oh this sounds like fun! Plus my drawing is bad enough that it’s bound to be cryptic… and maybe tending toward the not super useful which fits the OP perfectly lol
@subtext What degree and kind of silliness are you looking for? Merely not useful to adventurers, embarrassing in some way, implausible that they'd even exist...?
I like things that players would have fun with, but aren’t “useful” in the sense that it becomes a utility item they’re using every game. Something that can be a joke!
@subtext
Rod of Tattoos: As an attack, you can point this rod at someone within 30' and imagine a still image on an exposed patch of that person's skin. This will cause the desired image to appear on the person's skin for 1 minute.
If you maintain concentration on the effect for the full minute, without the rod leaving your grasp and without you or the subject leaving range of each other, the image becomes permanent, unless removed by Remove Curse.
A DM once gave me a necklace that could only be worn by neutral or worse alignments, and with a thought it would cause a torrential downpour of blood. The blood required a constitution check to prevent characters from puking. That was a pretty neat item.
I always try to have 2 Immovable Rods with my character so I basically have an infinite ladder. You can lock and unlock each rod and use them like rungs to climb things, cross gaps, etc. And they're not really rare or expensive.
Maybe add the opposite of those; rods that never stop moving. Unstoppable Rods.