https://www.cnet.com/news/the-best-last-minute-christmas-gift-is-the-tile-mate-for-16/

That's one option. Another is the new Tile Pro in a two-pack for $44.99. I'll explain the differences below.

For those unfamiliar with them, the Tiles are Bluetooth-tethered locators. Pair one with your phone, then attach it to a keychain or something else that routinely goes missing. When you want to find that thing, just tap the Tile app and the Tile rings.