I don't know how complete it is, but there's a list on MobyGames: https://www.mobygames.com/game-group/games-with-boss-key/offset,0/so,1a/ https://www.mobygames

I don't know how complete it is, but there's a list on MobyGames: https://www.mobygames.com/game-group/games-with-boss-key/offset,0/so,1a/ https://www.mobygames.com/game-group/games-with-boss-key/off...