I personally would say mine is probably Rockstar North or the original Bungie. Grand Theft Auto is probably my most fondest memories as a gamer, and all the games are legitimately very good.
Bungie used to be better before Destiny and they were still making Halo, would still be a close second for me.
Naughty Dog is up there as well, I didn't enjoy The Last of Us 2 as much as the first but loved all their other games. Especially the Uncharted series.
The original Infinity Ward that made Modern Warfare 1 & 2 were incredible too. Loved those Campaigns, and some of my fondest multiplayer experiences.
I didn't list every developer because it would take way too long, and there is too many, but I tried to get the most common ones in. Might have missed some.
Bungie used to be better before Destiny and they were still making Halo, would still be a close second for me.
Naughty Dog is up there as well, I didn't enjoy The Last of Us 2 as much as the first but loved all their other games. Especially the Uncharted series.
The original Infinity Ward that made Modern Warfare 1 & 2 were incredible too. Loved those Campaigns, and some of my fondest multiplayer experiences.
I didn't list every developer because it would take way too long, and there is too many, but I tried to get the most common ones in. Might have missed some.