I used the Xbox Design Lab to (almost) make a GameCube controller | TechRadar
My Hybrid Xbox/Gamecube controller : r/customcontrollers
PowerA GameCube Style Wireless Controller for Nintendo Switch | Nintendo Switch Wireless controllers. Officially licensed. | PowerA
Switch Pro controller on PC: Bluetooth guide | PC Gamer
Amazon.com: TALK WORKS Wired GameCube Controller - Gaming Controller Compatible with Nintendo Switch - USB-A Connection - Nintendo Switch Controls And Turbo Function - 9ft Cable - Black : Video Games
Nintendo Controller for GameCube (Styles May Vary) | GameStop
PowerA GameCube Style Wired Controller for Nintendo Switch | Nintendo Switch Wired controllers. Officially licensed. | PowerA
Nintendo Controller for GameCube (Styles May Vary) | GameStop
Putting Xbox One Sticks on a Gamecube Controller - YouTube