We are constantly pimping the Magic NS Adapter because it does just that.
It's $20 and allows you to use the following controllers wired or wireless, as easily as if they were supported natively, on a Switch, PC or Android device.
Supported controllers include the following:
Dualshock 4 (with rumble and gyro support)
Dualshock 3
Xbox One
Xbox 360
Wii U Pro
Wii/Classic Mini Console Classic Controllers via Wii Remote
USB HID
JoyCons (for PC & Android)
Switch Pro (for PC & Android)
The damn thing even supports multiple wireless connections at once.
I have one and have tested all but the Xbox controllers and they work flawlessly without lag. Saved me a shitload of money because I don't need to buy a Pro Controller or a new Arcade stick. I can use my HRAP 4 fightstick just by plugging it in, and because it comes with a USB C adapter it's like I have a mini arcade machine in tabletop mode.
The Wii TvC stick pictured here works great. I added side buttons for pinball :-)
As a side note, you can use you SNES/NES Classic Mini controllers too since they are Classic Controllers.
While we're on it, the TvC, Tekken Tag 2 and other Wii arcade sticks work on SNES/NES Classic Mini consoles!
8bitdo's adapter does everything the Magic NS does but it does not support wired controllers.
i bought the 8bit one, but i don't think it supports multiple controllers at the same time. Still it works with the wiiu pro flawlessly at least :)