This Nintendo Switch adapter turns your GameCube controllers wireless - The Verge
I figured out a way of connecting GameCube Controllers to Nintendo Switch without the Dock, all you need is a USB to USB C Adapter and Nintendo's New adjustable kickstand that's releasing
TTX Tech GameCube Controller Adapter for Wii U and Switch - Micro Center
GameCube controller support comes to Nintendo Switch - Polygon
Amazon.com: Gamecube Controller Adapter for Switch/Switch OLED.Gamecube Adapter Compatible with PC Wii U.Adapter with 4 Ports 6 FT(1.8M) Cable Support Turbo and Vibration Features Super Smash Bros : Video Games
MAYFLASH 2 Ports GC GameCube Controller Adapter for Wii U PC USB Nintendo Switch 6910201504099 | eBay
GAMECUBE CONTROLLER ADAPTER FOR SWITCH (ALSO WII U / PC) - Cables - Nintendo Switch - Nintendo
Amazon.com: GameCube Controller Adapter : Video Games