I simply use a Breloom for brute force, as it's ended up as one of the sweeper elements on my own test teams.
EV's: 6 HP, 252 Attack, and 252 Speed. I always run it with an Adamant Nature, because usually Breloom hits only once...And I want once to be enough in as many cases as possible.
I like to run it with Poison Heal, give it a Toxic Orb, and that eliminates status problems other than attraction and confusion.
I use Facade because of its 140 power, due to its poison.
Seed Bomb makes an epic STAB move, and gets the job done, on many pokemon, especially on many with Sandstorm teams, with the Rock and Ground elements.
Sky Uppercut, while not quite as powerful, still deals a good blow because it's a good STAB move. Breloom hits hard with Rock and Steel types that try to wall it.
For Fire and Flying types, Stone Edge usually knocks them down a notch or two...Even if he doesn't score a critical hit on them.
I usually sub out Breloom with a Spiritomb, or another good pokemon, as soon as a Psychic, or a really fast Flying-type comes out to play.
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Counters: Ground/Fire, or Ground/Flying types, and most provided it's faster. Stone Edge isn't SE, and Sky Uppercut simply doesn't do it. Seed Bomb also hits neutral, like Stone Edge, so if I have no other choice, I simply spam with that...Or Facade, if that proves to be more effective.
As I mentioned, Psychic types usually make it run like the wind, and many good Flying types also outspeed it.
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Backup for counters: As I mentioned, Spiritomb makes an excellent sub for the Psychic types, as it is both Ghost and Dark type, making it have absolutely no type weaknesses. A Taunt usually stops many walls in their tracks, if a wall is what I switch into. Shadow Ball and Dark Pulse usually end most Psychic types rather effectively, with two, possibly three hits. Destiny Bond is for desperation measures, if I know that it's toast...
Weavile, with Ice Punch and Night Slash usually also deals with most counters to Breloom, but is rather weak, and is really only used for both speed and brute force, like Breloom. I would only sub Weavile into a wall, to sweep it as fast as possible.