Naughty Dog for me. Ever since that acquisition, they have always crafted high quality games. There are definitely other hits for Sony like Guerilla Games and Media Molecule, but Naughty Dog just has a better track record.
Monolith Soft is my close second. Nintendo needed an RPG machine after Square Enix left them; another developer to add alongside with Retro Studios no less. Since then, the Xeno series definitely has helped Nintendo in their already large 1st party exclusives and capture some Xeno fans in the process.
" It has never been about acknowledgement when you achieve something. When you are acknowledged, then and only then can you achieve something. Always have your friends first to achieve your goals later." - OnlyForDisplay