Updated: Added hid-mitm. It supports GamePads like Xbox, PS4, and so on without using 8-bitdo.
How to use it: Using PC, Android, iOS, or Linux, download this companion apps package
Extract the zip and run the app depending on the platform you want to use.
If you want to run in PC, run start.bat.
Set the IP of your Switch. Remember your PC and your Switch must be in the same network.
In this case, once you run the app, and with the IP set, connect a GamePad. If it is detected, as soon you manage your gamepad, the movements will be mirrored to your switch, and you will manage the switch. Very cool.
Further info here:
https://github.com/jakibaki/hid-mitm/blob/master/README.md