just for fun.
Bethesda Game Studios - Elder Scroll
ZeniMax Online Studios - Elder scroll Online
Id Software - Halo and Doom (Halo Slipspace Engine is no more)
Arkane Studios - Horror Starcraft FPS game
Machine Games - Doom and Halo (Halo Slipspace Engine is no more)
Tango Gameworks - Mobile game based on Doom
Alpha Dog Games - Mobile game based on Elder Scroll
Roundhouse Studios - Mobile game based on Fallout.
Blizzard - classic War Craft, Diablo and starcraft games. Also, all mobile games from these 3.
Treyarch - CoD
Infinity Ward - CoD
High Moon Studios - CoD
Toys for Bob - new Skylanders and Mobile Skylanders. ( Banjo-Kazooie and conkers are on skylanders)
Raven Software - CoD
Sledgehammer Games - CoD
Beenox - CoD
Radical Entertainment - support studio
Rare - new Skylanders and Mobile Skylanders.( Banjo-Kazooie and conkers are on skylanders)
343 Industries - Halo and Halo mobile. (Halo Slipspace Engine is no more)
The Coalition - Overwatch
Mojang - Minecraft
Turn 10- Forza
Playground Games - Forza Horizon and Elder Scroll 3rd person action game.
Undead Labs - Support studio / small mobile games.
Compulsion Games - Support studio / small mobile games.
Double Fine - Original new IPs, a creative studio.
Ninja Theory - Diablo 3rd person action game.
Obsidian Entertainment - Fallout
InXile Entertainment - Fallout
The Initiative - new IP? perhaps more Overwatch?