Paradox Dev Studio, Haemimont Games, Blind Mind Studios, Enlight Software, Egosoft, Katauri Interactive, Introversion.

To a lesser extent - Positech Games, Sports Interactive, Firefly Studios, Tilted Mill, the Creative Assembly, Firaxis Games, Valve, Piranha Bytes, Tale Worlds, Altar Games, 4HEAD Studios/Cranberry Production, Frontier Developments.

Some no longer existant ones - Black Sea Studios, Ascaron Entertainment and especially the excellent PopTop Software.

I may have forgotten quite a few.

theOnesThatMakeTheGamesWhereYouShootDemDubleBarrelShotgunWith360NOSCOPE

Valve, i like their Dota 2 games alot.

and

Sega, i like their Virtua Tennis 4 sport games alot.

Bethesda Softworks is my favorite publisher, the games they put out have a tendency to suck away large chunks of my life (445 hours between just Skyrim and Fallout NV).

CDProjektRED
Valve
NaughtyDog
Klei Entertainment
Supergiant Games

I like a lot of developers tbh. I love bethesda for their RPG's. Rockstar for open world games. And somewhere deep down I have a soft spot for ubisoft, although their servers on games suck.

Bethesda, despite their buggy games. I just like FO and Elder Scrolls

Developer: BlueByte , Related Designs
Publisher: Ubisoft

Because they make the best games and haters get mad at the DRM.

Innocent Grey. Yeah.

Klei Entertainment - for Don't Starve :D

Anything that's not EA.

On a more serious note, Bethesda, Valve, Klei Entertainment, 2K, Take-Two, Turn-10 (mostly because of Forza), Konami, Clover Studios (RIP), Rockstar, the list goes on and on.

Remedy, Valve.

Valve, Nemesys (I talked with them! :D), Klei, Rockstar and Wadjet Eye.

Blizzard. Only quality games, no DLC / preorder / microtransaction bullshit.

Westwood Studios because of the Dune franchise.

NISA, Atlus, xSeed; but they are distributors/localization teams and not actually developers.

crytek

2K, Firaxis, MicroProse (defunct) and QQP (defunct).

There's quite a few of them:

Obsidian Entertainment, CD Projekt Red, Valve, Eidos Montreal, Irrational Games, Ubisoft Montreal, Telltale Games, Bethesda Softworks, Square Enix and 2K Games.

I'd also mention pre-EA BioWare, they used to be my favorite devs until DA2 and ME3 happened (until they were indoctrinated by rEApers). :(

spiderweb software, firaxis, valve, and bethesda

Valve, CDPR.

Valve, Nintendo & Blizzard.

Nintendo, Atlus, XSEED, and Namco Bandai

Valve, CD Projekt Red, Rockstar (Yeah, they hate PC gamers but they make great games), Square Enix, Team Meat, THQ (RIP). Probably more that I'm just not thinking of right now.