286 Breloom

Counter is one of the best fast moves for PvP, use it and abuse it. 

Seed Bomb is a relatively low cost charge move that can be used often to shield bait. While Grass Knot is a much more powerful move, Breloom might not be able to use it enough due to its fragility. Sludge Bomb gives Breloom an option for some coverage while Dynamic Punch makes it more of a specialist. 

Known as a glass cannon in PvE, Breloom still somewhat maintains that reputation in PvP. Access to a good moveset allows Breloom to perform decently well even with a lack of bulk, since in the eyes of Breloom, the best defense is a good offense. Who needs bulk when your damage is so high? In practicality though, Breloom's vulnerability to 6 typings means it must be used with caution, since it can quickly fall if an opponent exploits Breloom's squishyness. 

A higher CP cap allows Breloom to flex its Attack stat more in Ultra League. Even though it doesn't have a lot of durability, Breloom's high offensive power makes short work of any opponent weak to its typing, including the Ground-types which give other Steel counters a lot more trouble. Obvious losses against the Psychic- and Ghost-type legendaries prevents Breloom from being a top meta pick. 

Breloom doesn't have the stats to compete well in Master League. A win against Dialga in Ultra League becomes a loss in Master League, which is unfortunate for our mushroom-kangaroo friend.