Amazon.com: Hyperkin 4-Port Controller Adapter for GameCube Compatible with Nintendo Switch/ Wii U/ PC : Video Games
Amazon.com: Mayflash GameCube Controller Adapter for Wii & Wii U (Dual Pack), White : Video Games
Gamecube Controller Adapter for Switch Gamecube Adapter Wii U and PC, Super Smash Bros Choice Support Four Gamecube Controller and 70IN Long Cable - Newegg.com
GameCube Controller Adapter for Wii U, Nintendo Switch and PC USB – Lexuma
NEXiLUX Nintendo Switch GameCube Controller Adapter for Wii U, PC USB – J&L Video Games New York City
Mayflash GameCube Controller Adapter for Wii U and PC USB (4 Port) - Walmart.com
Smash Wii U GameCube Controller and Adapter Unboxing - YouTube
GameCube Controller Adapter for Wii U, Nintendo Switch and PC USB – Lexuma