At Spaceworld 2000, it was announced that a version of the Gamecube Memory Card that would have expandable memory via an SD card would be released. However, this never came to fruition.

A similar device that allowed for the plugging in of an SD card into memory card slot was released alongside Dobutsu no Mori e+ in Japan, however this was only to take screenshots and did not allow for the saving of game data.
Contributed by Takahashi2212