Hardware Gamecube controller or Pro?

[Lallo]

I'm thinking of getting a Wii u to play games like Smash bros and Mario 3d world with my friends.
However I wonder is there any homebrew addon or something that has made the gamecube controller functional for other games than smash bros?

I have tons of gamecube controllers but I dont want to spend money on 4 Pro controllers (costs about 50-60 dollar where I live)

Or is there any place I can buy them cheap?

 

[xtheman]

https://gbatemp.net/threads/hid-to-vpad.424127/
This can use any HID controller, including gamecube (with the adapter).
The current release is gamepad only but a beta is out with pro spoofing too.