Software for the GameCube that were produced without the permission or knowledge of Nintendo.
Compared to the Wii's gargantuan homebrew scene, very little custom software was developed for the GameCube. This can be attributed to the already small following the GameCube had; even with a modchip and sliced CD-Rs made to fit the GameCube's tiny slot, homebrew just wasn't common and any existing emulation was premature. By all means, the GameCube saw little to no attention once the Wii came out, narrowing the focus even further. The only known unlicensed game to be sold at retail is MaxPlay Classic Games.