Atlas Games
Feng Shui, Unknown Armies and Over the Edge as well as other less well known games.

Chaosium Inc.
Makers of the excellent Call Of Cthulhu.

Delta Green
Shh, it's a conspiracy.

Fantasy Flight Games
Publishers of Warhammer Fantasy Roleplay

Pinnacle Entertainment
Publishers of the classic Deadlands.

Wizards of the Coast
Publishers of Dungeons and Dragons.