In addition to Xbox 360 and Xbox One controllers, it was discovered that Steam Link also supports PS3 and PS4 controllers. I decided to give my Wii U Pro controller a shot. :
Steam Link update enables Xbox One S controller Bluetooth compatibility | VentureBeat
How To Connect Bluetooth To Xbox One | Know How to Connect the Steam Link with Xbox One S Controller - MustTech News
Fix: Steam Link Setup 'No Host Computers Found' - Appuals.com
Will Xbox keyboard controller add on work through steam link? Wanting to pay wow classic with this setup. : r/Steam_Link