Seinxon is offering a new AirTag alternative that is particularly thin and can be easily hidden or stored in a wallet. Another advantage is that the device can be recharged, which also helps avoid waste.https://www.notebookcheck.net/Seinxon-New-Apple-AirTag-alternative-in-credit-card-form-is-rechargeable-has-NFC-and-can-be-loud.784937.0.html
I'm honestly surprised these aren't just lame Bluetooth tags but actually work with the airtag network!
The downside is that the "wireless charging" is just a usb-c clip, small and easily lost, that still has to attach to two metal contacts on your card, no placing your wallet on your magnetic phone charger or charging without removing your card from your wallet.