There's a few developers I think of fondly:

BioWare: Is probably top of the list. The games I've played from them have all been excellent, and even my least favoured games from them still rank highly in my memory, even if there were flaws that should have been corrected. I love in particular to gender and sexual diversity in their games, especially towards the LGBT community. Special mention must be made to Krem from DA: I, the first Trans character I can remember in a video game. Long may it continue.

Square Enix: They may have fallen slightly in more recent years, but they still churn out good (if not groundbreaking) entries in the Final Fantasy series, and are attempting to right the wrongs of the last few years. Doubts still linger, but hopefully the next year or two will clear them more definitively.

Atlus: I know them for the Persona series, and what a series. I love games that seek to de-construct tropes, and Persona 4 and 3 do just that. The character interactions are fantastic, tied together with a decent combat system. But really, you play Persona for the people, not the fighting.