Softdisk Publishing was a provider of diskette based progams, who is probably most famous for providing an incubator for id Software. Under the "Gamer's Edge" banner (a bi-monthly software "magazine") many of the id Software founders published games like Catacomb Abyss and Dangerous Dave.
Game developer / publisher profile
Alien Rampage (1996)
The Catacomb Abyss 3D (1992)
Commander Keen: Keen Dreams (1991)
Rescue Rover (1991)
Dangerous Dave (1990)
Galactic Battle (1990)