So I was ripping sprites from Bomberman Land 2 with Dolphin, and I found some unused ones.
First of all, even though I was ripping sprites from the Gamecube version, there were button icons leftover from the PS2 version (which was released first). Here is an example with the icons from the Bomb Factory mini-game:
Another set of unused sprites I found are leftovers from Bomberman Kart, which are unused in both versions. These include old character icons and 9th to 12th position indicators:
There may have been more unused sprites I missed, but those were the most interesting to me. I also wasn't sure on whenever or not I should post this in the emulation section, so I am posting it here until further notice.