Below are all the devices that have been tested. Operating systems that have been tested are Windows, MacOS, Android, iOS, Ubuntu, Arch Linux. These are not the only devices that work, but these have been tested and verified. Most keyboards should work flawlessly, and if one doesn't work, you can let me know so I can fix it.
Keyboards
There have been reports of some QMK functionalities not working 100% propertly, i.e. Mod Tap/Tap Dance. Others have reported that all functionalities work, so your mileage may vary. Reducing the polling rate in the QMK firmware seems to help with this. 1000Hz polling rate is too high and can throttle the Bluetooth connection. A polling rate of 300Hz or less is recommended. Keyboards that act like HUBs (and actual HUBs) are currently not supported.
Mice
There is some noticeable latency/jittery when using mice, but they do work