onesvenus
Member
Guerrilla developed games for the Game Boy and the Xbox,None of those developers were multiplatform that I can remember. A lot of them were effectively 2nd party developers that pretty much exclusively made PlayStation games.
Naughty dog developed games for the Mega Drive and the 3DO previously to them being bought, and Sucker Punch for the N64.
Obviously Sony's support is what made them into what they are today but do not pretend that Sony did not buy their way into the videogame industry.