I really like Tile and have been using it for about two years. I have even bought them for both my brother and brother in law.
Tile is a little device that connects to your phone via Bluetooth; it has an accompanying app that you can use to make a sound play on the Tile. So I have a Tile in my wallet and on my keys; if I lose either, I open the app and then select the item I have lost. The Tile starts ringing, and on the screen I am shown a little graphic that explains how close I am to the item.
I discovered tile in an Airport technology shop where they were selling an original Tile of about £10. I keep this one in my wallet. I then bought two stick on tiles and put one on my remote control and one on my car key.

Tile actually make lots of different shapes and sizes and ideally id have bought a wallet credit card size Tile and a keychain one for my Car keys. However, I bought the types I did because they were on offer at the time.
I lose my keys at least once a week (I know I have a problem); funnily enough, I often lose my phone too, so my procedure to find anything is: Use my Apple watch to beep my phone then use my phone to beep my Tiles. Tile is available as an app on my watch, but I have found it to be useless and is much more reliable on the phone.