https://templates.blakadder.com/ has almost 3,000 devices flashable onto Tasmota firmware.

For older Tuya devices there's https://github.com/tuya-cloudcutter/tuya-cloudcutter

OpenBeken https://github.com/openshwprojects/OpenBK7231T_App covers 800 of the newer generation Tuya devices.

And there's a large community adapting ESP32 devices onto https://esphome.io/