Ill just list them based on my favorite games of all time, however in certain cases, they are no longer "the best".
CDPR - no question here, Witcher and Cyberpunk are pretty much one of the greatest games ever made.
Bioware - yep, I know, but you can't deny their history with KOTOR, Mass Effect trilogy and Dragon Age Origins(wasnt a fan of BG at that time), these games paved the way for a lot of other developers including CDPR stuff and despite some duds I still enjoyed even their latest games like Veilguard and Andromeda.
Larian - no, not because of BG3 even if its a good game, it's not one of my favorites, but Divinity Original Sin 2! I love this game and its still my favorite crpg.
id - Doom, need I say more? Doom Eternal is the best shooter ever made.
Eidos Monteal - thief(yes I liked the new one lol), DXHR amazing game always replaying it, DXMD not the best but still good, TR was fine.
Arkane Studios - yep, another one similar to Bioware, but Prey, Dishonored 1 and 2 are my favorite games of all time so yeah
Naughty Dog - Uncharted and TLOU, nothing more to add, Joel and Nate are peak main characters and nothing has surpassed them yet.
RGG studio - Yakuza, still awesome after so many years, they have a few duds, but the main series are awesome fun
Rocksteady - they fucked up bad with SS, but Batman Arkham trilogy is peak Batman and nothing in the media, movies included has surpassed it.
Insomniac - Spider-Man games like the Batman trilogy have the best Spider-Man and I loved all 3 of them.
Bonus: IO Interactive - for Hitman and Freedom Fighters, Croteam - SS and Talos, Rockstar - not a huge fan of GTA games, but RDR2 is top dog of all top dogs.