The only MMORPG-type game that comes to mind with any kind of pet-related gimmickry is that of Free Realms. Though, I'm wondering what you specifically have in mind, whether it's the pet itself that does the questing, leveling, and battles, or whether it's a game that features pet creatures.
If it's the former, I'm not too knowledgeable on the database of MMO games, and specifically not ones where the pet itself is under your control.
There is a huge fan base of pet based MMORPGS but no good games that stand out.
not quite what I had in mind, but thanks
I was going for more of a PVP type game, customisable classes, fantasy based etc.
Good buys are; Knack, Killzone: Shadow Fall, Watch Dogs, AssassinCreed: Black Flag, Drive Club, Infamous Secound Son, Order 1888 or 1880 or something like so.
Sorry, not seeing it. Not trying to flame, I just really didn't understand.