>>42012230I've found that the G.Max Eevee and G.Max Pikachu you get in game are really good for breeding if you're trying to breed anything in the Field egg group. Both of them have 6IVs and they've been extremely helpful to me.
Some mons to breed shinies of would probably be Applin, Eevee, Nickit, and Grapploct (To name a few.)
Battle wise, Dracovish but that isn't really breeding, rather just soft resetting the fossil. A lot of the included mons from past gen metas will work here so as long as you know what was kino in gen 7 you'll be fine.
Obstagoon is eh. I just flame orb/guts/facade with it after an obstruct. It's UU so take it as you will.