ZedLabz 16MB memory card for Nintendo GameCube GC & Wii 251 block - wh
Nintendo Support: How to View Nintendo GameCube Memory Card Data
How To Backup Your Physical GameCube Memory Card For Emulation - Modded GC/ Wii Required - YouTube
Beware of fake memory cards being sold with official packaging. This thing shorted out my Wii and GameCube when plugged in. Thank god they still work. : r/Gamecube