Started with standard Mega Swampert, but replaced Earthquake with Superpower to help with the Kartana/Ferrothorn matchup and to prevent Grassy Terrain from getting in Swampert's way. Next is standard-ish Pelipper, but I went with Brine over Hydro Pump because most of this team's attacks are going to bring the opposing Pokemon low enough that Brine will double in power and basically become a more accurate Hydro Pump with more PP. I wanted a Trick Room mode and a mon that could resist Grass, so I went with Bronzong. The Defense investment allows it to live a max Attack Hoopa-Unbound Hyperspace Fury. I gave it Rain Dance because I didn't want to solely rely on Pelipper for getting up rain, since I sacrificed Damp Rock for Focus Sash. Snorlax is here just to take advantage of the Trick Room mode since it can hit so hard. Tapu Bulu was added because I wanted a safe switch in for Pelipper into Electric types. Sub is there for whenever Bulu gets a free turn or when the Mago Berry needs to heal it up, and the last slot was originally HP Fire, but it conflicted a bit too much with rain to the point where I was trying to avoid bringing in Pelipper to get full powered HP Fires off, and it was also pretty pitiful damage on Ferrothorn, so I switched it to Superpower. Magnezone was the last one here because it has pretty respectable Special Attack and gets Sturdy, so as long as it's not doubled into it can get its Z move off, which does a monstrous amount of damage.
The team plays pretty simple. Getting the control off asap had proven to be quite ideal, but not necessary. Bronzong + Swampert is a good lead, since Bronzong can either go for Rain Dance and get Swampert going immediately (or switch out into Pelipper) or go for Trick Room to get the slower members of the team going, though it shouldn't be considered the lead for all matches, such as opposing Trick Room teams or facing down a Scarf Tyranitar. Once a form of speed control is up, the team is about getting a bunch of offense off. Just barrage the opponent with strong attacks.