Valve

Right now? Valve.

Throughout history? Valve, ID, everyone bought out and shut down by EA throughout the 80's and 90's, EA, Ubisoft, Epic, Interplay, uh... There's so many I'm having a hard time remembering who did what.

Some of these aren't necessarily influencial or fundamental in a good way; the industry would not be what it is without them, though. 🤷🏻‍♂️

Back in the day, Bioware. Original Baldurs Gate. Neverwinter Nights with its neverending modules and such.

Mass Effect and Dragon Age O were a new way to engage the RPG.

How far the mighty have fallen.

John von Neumann,

John and Adrian Carmack,

Chris Sawyer,

Maddy Thorson and Lena Raine,

Jeremy Soule

Bullfrog

Any indies or AA studios really, those are the responsible for actually fun and finished products. Without them and their hits the industry will be a barren wasteland of predatory monetization and boring games-as-a-chore landscape.

Valve is the obvious option if you're looking for more modern devs.

Microprose.

Larian.

Purely from a game design standpoint and ignoring all corporate and sales considerations, Valve.

Half-Life, Half-Life 2, and Half-Life: Alyx are literally three separate Citizen Kanes of video games. All took immense steps forward in the direction of removing the layers of abstraction between video games and human experience.

From a meta perspective that considers things like the process of game development and the accessibility of video games on PC, also Valve. Steam has done wonders in the way of unifying (to the best of Valve’s ability) the user experience of DRM into a very manageable interface. Proton has taken the barriers to entry into the realm of video games down to the fucking studs. The Steam Deck is laying the foundation for eliminating the dominance of any one video game hardware manufacturer.

I’d be hard-pressed to say any other development studio has been more fundamental to the gaming industry period, let alone PC gaming.

Obsidian have some unique games under their belt

Blizzard before they turned to shit

Logitech.

Interplay/Black Isle, pre-EA Bioware, Troika, Obsidian, Chris Sawyer, Larian, Lucas Arts, Valve, Gearbox had it's time in the sun, as did Mojang.