2K Games (details)
Accolade (details)
Activision (details)
Atari (details, and the game console) This is Infogrames' alias, not the real Atari which is dead and gone.
Big Fish Games (details)
BioWare (details)
Black Isle Studios (details)
Blizzard (details)
Buena Vista (details)
Capcom (details)
Cartoon Network Games⁑ (details, by group)
Codemasters (details)
Disney (details)
Electronic Arts (details)
Firaxis Games (details)
GT Interactive (details)
IBM⁑ (details)
id Software (details)
Infocom (details)
Infogrames (details)
Interplay Entertainment (details)
Konami (details)
(by group)
LucasArts (Now owned by Disney, see above also) (details)
Maxis (details)
Microsoft (details)
Midway Games (details)
Ocean(details)
Namco Bandai Games⁑ (details)
Paradox Interactive⁑ (details)
Renegade Software⁑ (details)
Revolution Software (details)
SEGA (details)
Sierra (details)
Sony Computer Entertainment (details)
SNK (details)
Square Enix (details)
Take-Two Interactive (details)
Taito (details)
Team17 (details)
THQ (details)
U.S. Army (details)
Ubisoft (details)
Valve⁑ (details)
Warner Bros. Interactive Entertainment⁂ (details)
Zenimax (details)
Indirectly:
Marvel by group (details)
Nintendo (no Intel hardware Linux games yet, But they made an NES emulator for Linux on ARM and published 38 games) *
⁂ Time-Warner seems to take a paranoid-schizophrenic actions concerning Linux. Refusing to support platforms without the DRM they like (even when the platform does have their preferred DRMs) yet occasionally releasing products for platforms without any consideration for DRM, the value of the product, or the likelihood of illegal copies detrimental to profits. And, announcing games for Linux only to later refuse to publish them.
⁑ While some companies are dipping their toes, experimenting and such, These companies are committed to the idea that their is a Linux gaming market and have plans to make use of it.
* Nintendo