I'd have to say: Commercial Type (https://commercialtype.com/) and Lineto definitely have some of the best heavy-hitting, contemporary and subtly stylish fonts out there (http://lineto.com/)
I like this little foundry swiss
Hoefler Frere-Jones (R.I.P.)
Typetogether! They make some of the best fonts for copytext.
House industries : http://www.houseind.com
https://www.p22.com/ is a good one
For "serious" type, mine would definitely be Hoefler Frere-Jones, but for personality, it's Blambot.
I think Suitcase Type Foundry has some fresh and interesintg stuff for new releases in non orthodox way. www.suitcasetype.com
At the same time DSType has an extensive catalgoue with neo-traditional works in slab ways. Its link: http://www.dstype.com
House Industries is mine!
I like the quality offered up from Fontsmith and Dalton Maag, Typotheque, having said that, i wouldn't like ALL of their work, some of them i'd just never use.
Colophon at the moment, Lineto. So many out there now, hard to choose
monokrom is a pretty awesome foundry. Just wish they had more fonts!
Fenotype and Sudtipo.