AirTags only come in a single size and shape that only makes sense for larger container objects

Kind of. Apple's Find My network is open to third party accessory makers. Here's a card-shaped one https://chipolo.net/en/products/chipolo-card-spot I don't believe third party accessories support the compass-style precision finding though.

While technically true, there are non-AirTag third-party devices you can buy that still work with Find My: https://www.macrumors.com/guide/find-my-network-accessory-pr... Both variants you list are supported by Chipolo: https://chipolo.net/en/products/category/chipolo-spot

AirTags really should have a hole on the edge. Then could attach a lanyard for keychain or strap without needing an adapter.

Unfortunately the wallet trackers are compromised by the fact that most nice wallets come with RFID (and BLE) blocking linings nowadays... Hang onto your old RF-transparent wallet, because RFID blocking has become a standard bullet-point feature they all have to have now.

FWIW I've had success with this AirTag card thing: https://www.thingiverse.com/thing:4849497 . It's flat enough to fit in my wallet without distorting it too much.

Insane that this seems to be getting downvoted (I assume? It's faded to light gray) just because you are daring to question the superiority of the Apple Solution.

It's weird to me that people actually have this problem often enough that they go out of their way to research and buy a product to try to solve it. I literally never lose my phone or wallet. There's like three different places I put my phone in different areas of the house, and only one where I put my wallet and keys as soon as I enter. I would like an airtag to put on my bike or laptop or other high value item to track it if stolen, but I'm not about to buy Apple stuff.