In sun/moon. Different berries are found on different islands, aren't they?
Every berry is can be found on route 10. They are:
Pomeg: -10 HP EVs
Kelpsy: -10 Attack EVs
Qualot: -10 Defense EVs
Hondew: -10 Special Attack EVs
Grepa: -10 Special Defense EVs
Tamato: -10 Speed EVs (Tamato can also be obtained through free samples at the Thrifty Megamart.)