You can use the Smash Brothers Gamecube adapter in portable mode with a USB C adapter (Rumble works too) : r/NintendoSwitch
Finally found one! : r/smashbros
How to Connect a GameCube Controller to the Switch - Howchoo
Everyone talking about how they want Gamecube controllers on their Switch, but how do I plug this thing in? : r/Gamecube
Want to play Super Mario Sunshine with a GameCube controller with original controls on Switch? You can remap controls for the GameCube controller with the 8bitdo Gbros. adapter : r/NintendoSwitch
How Close Is The New 2018 Gamecube Controller To The Original? - YouTube
Thought id share this! Wireless Gamecube controller for Switch from AliExpress 😄 : r/Switch
Wireless GameCube Controllers for Switch : r/NintendoSwitch
The Gamecube controller is my favourite it fits perfectly in your hand it's comfortable and the analog stick is amazing! a well made controller. : r/ Gamecube
3D Printed Dock + Gamecube Adapter : r/NintendoSwitch
Gamecube Nintendo Switch Dock I made. : r/NintendoSwitch
Anyone else use a Gamecube controller? (I usually play on Xbox but i'm in rehab rn and only have my switch) : r/RocketLeague
GameCube controller with cuphead it actually kinda works pretty good : r/ Switch
Power wireless GameCube(silver) comparison to other controllers in case anyone wanted a visual comparison : r/NintendoSwitch
Is there any way to use this Switch GameCube USB controller ? : r/OpenEmu
Walmart] PowerA Wireless Gamecube Controller for Nintendo Switch - $36 (YMMV) : r/NintendoSwitchDeals
Do not buy the power A wireless gamecube controller. 2 months in. Took excellent care of it, never dropped it, and stored it in a beats case. Smash is unplayable : r/smashbros
Just found out the Wii-U adapter works on switch! It's time to get serious about smash. : r/gaming
It's technically possible to play Ultimate with GameCube controllers (and rumble) in handheld mode. : r/smashbros
Introducing the SwitchCube! : r/Switch
GameCube Controller Adapter up for Pre-Order for $20 for the Switch : r/NintendoSwitch
Target/US] PowerA Wired GameCube Controller for Nintendo Switch - Black - $14.99 : r/NintendoSwitchDeals
Target / USA] PowerA Wireless GameCube Controller for Nintendo Switch - Purple - $24.60 : r/NintendoSwitchDeals
Switch dock with compatible GameCube controller : r/gaming