I'm actually part of a league that is composed of mono-type teams. I'm the Ground leader this gen (previously Bug. I even was the final E4 member) and while I haven't had as much success as last gen, I'm still in the E4 position(position is determined by a round robin tournament between monotype teams). Encourage Nidoqueen gets up my toxic spikes and then Gliscor stalls out anything that can't dish out over 75% of it's HP in a turn or is slower than it. I usually clean up the match with an Excadrill sweep, as it's only Steels and poison types left after that. Sometimes I struggle with opposing Gliscor, but that's what Mamoswine is for. If you're running monoground and had troubles with bulky waters like I did, try out Gastrodon with Storm Drain. He took the place of Unaware Quagsire, but the Quag's inability to take special water hits kinda annoyed me. Monotype teams are seriously underrated, as I've been beat by them a couple times myself.