Been a bit since I posted there, but new Sega 8-bit roms including rare games and plenty of prototypes are regularly being released on SMS Power.
Ttoriui Moheom (KR)
Wonder Boy in Monster Land [Proto]
Gain Ground [Proto]
James "Buster" Douglas Knockout Boxing [Proto]
Impossible Mission [Proto]
Indiana Jones and the Last Crusade [Proto]
Blade Eagle 3-D [Proto]
Castle of Illusion - Starring Mickey Mouse [Demo]
Moonwalker (Michael Jackson's) [Proto]
Hwarang-ui Geom (KR)
Super Boy 4 (KR)
SMS Power is always looking for help to uncover and release oddities and prototypes, free of hassle since 1997.