A cool project I made in 2016. It was even technically finished (this is just the debug view)
Basically, this was a controller for Android. It would pair with your game on the PC over Wifi and download a custom skin and button layout from it.
It would then stream input data to the game to act as a full controller.
Unfortunately, the latency between inputs was just too bad, so I had to shelve it. If adhoc connections between Android and Windows actually worked, I might have continued with this. Until I can find a better way of doing this, it has to be on hold forever, which is sad.