Wii U can use two GameCube controller adapters
GameCube Controller Adapter for Wii U, Nintendo Switch and PC USB – Lexuma
Wii U Gamecube Controller Adapter - Brook Gaming
NEXiLUX Nintendo Switch GameCube Controller Adapter for Wii U, PC USB – J&L Video Games New York City
CLOUDREAM Gamecube Controller Adapter for Switch Gamecube Adapter Wii U and PC, Super Smash Bros Choice Support Four Gamecube Controller and 70IN Long Cable
gamecube Controller Adapter (For Switch/WiiU/PC) – YCCTEAM
Wii U Gamecube Controller Adapter , Png Download, Transparent Png , Transparent Png Image - PNGitem
Wii U 4 Port Gamecube Controller Adapter
TTX Tech GameCube Controller Adapter for Wii U and Switch - Micro Center
GameCube Controller Adapter | Switch GameCube Adapter
Mayflash 4 Ports For Gamecube Controllers Adapter Converter For WIIU S
Gamecube Controller Adapter for Wii U PC USB and Switch 4 Ports & No Need Driver | eBay
Y Team Controller Adapter for Gamecube, Compatible with Nintendo Switch, Super Smash Bros Switch Gamecube Adapter for WII U/PC with 4 Port
How to Use Wii U Gamecube Adapter on Dolphin (PC) - YouTube
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
GameCube Controller Adapter 4 port for nintendo Switch Wii U & PC USB NEW TURBO 606098869866 | eBay
Gamecube 4 Port Controller Adapter for Wii U And Switch by Mars Devices - Walmart.com
Nintendo GameCube Controller Adapter for Switch / Wii U / PC Tested Working | eBay
