Over 300 prototype Sonic games for multiple different systems have been acquired by the Videogame Preservation Museum but they're asking for £61,000 (81k USD) to dump and preserve them all, otherwise these prototypes will become lost media.
https://www.sonicstadium.org/news/games/video-game-preservation-museum-obscure-gamers-launch-fundraiser-to-preserve-300-gbadsdsi3ds-sega-prototype-carts-r2919/