I have three Bikes which I deeply care about and do not want stolen or lost. So I got three different Apple Airtags and 2 different cases/ holders which I think blend in pretty well to my bikes.

This is not a paid ad, I just thought these were decent products and would recommend!

Product Names found on Amazon, I do not have affiliate links.

PerfiPro Airtag Bike Mount, Hidden Bike GPS Tracker Case for Apple Airtag, Airtag Bike Seatpost Reflector Mounts, AntiTheft Airtag Holder for Bike, Electric Bicycle, Scooter (2 Pack)

Elevation Lab TagVault AirTag Bike Security Mount The Waterproof AirTag Bike Holder | Hidden Under Bottle Cage or Alone | Titanium Security Screws with Driver

Bike Names:
Scott Ransom Contessa XL
2020 Cannondale Habit Neo 4 EBike
RadRover Electric Fat Bike Version 5