This is a set I've used before, and it's not too shabby. I don't remember which Hidden Power I used though, but I'd say Rock would be the most useful since it counters Ice, Fire, Flying, and Bug, and also gives you pretty much the best coverage you can get. This does leave you unable to hit Doublade/Aegislash or Toxicroak for SE damage, though, and it's probably not worth it to face off against a Flying type that's neutral to Rock (such as Skarmory or Gligar/Gliscor). You could also replace Leaf Storm for Substitute and go with a Petaya Berry if you think you can scare the opponent out and Sub up to the point that the Berry activates; it's riskier and requires more time to set up, but has a bigger payoff than being able to Leaf Storm twice in a row.
HP Fire requires 31/30/31/30/30/31, Ice needs 31/31/31/30/31/31, and Rock takes 31/31/30/30/31/30. No matter what, your Speed's going to have to take a hit.
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Alrighty, my turn to try for a lesser-used pokemon I might want on a UU team (or at least RU when it comes time for that tier to be analyzed):
Stunfisk @ Leftovers
Static/Sand Veil
Modest/Quiet
252 HP, 252 SpAtt, 4 Def
- Discharge
- Earth Power
- Sludge Bomb
- Scald/Muddy Water/Stealth Rock/Sandstorm
Oh, how I wish this little guy got Serene Grace; he just seems like the Dunsparce of Gen 5 to me. He'd do so well with it. Anyway, with his low 32 base Speed and decent 109/84/99 bulk, Stunfisk seems like a perfect fit for a Trick Room team. All of his primary attacks is a 30% chance to do something nasty to the opponent, whether it be Paralysis, Poison, Burn, accuracy drop, or SpDef drop. Seriously, I think he'd be at the minimum a strong UU pokemon if he had Serene Grace to back him up. Instead, though, he has Static, which is probably his best option outside of Sand, or Sand Veil if he IS in Sand. Being an Electric/Ground type does make him weak to several common attacking types, though, and his last ability, Limber, is completely useless with Gen 6 granting Electric types immunity to Paralysis. Static/Quiet with 0 IVs in Speed would be best for the Trick Room variant, while Sand Veil/Modest is better for the Sandstorm variant. A bonus to his movepool besides the rate of dealing afflictions is his coverage; Electric/Ground/Poison covers a wide variety of threats, and throwing in Water gives you perfect neutral coverage save for Shedinja. If you wish, in place of his Water move, he could be used to set up Stealth Rock or Sandstorm, or possibly for a more accurate status move.
Aggron @ Iron Ball
Heavy Metal
Brave
252 HP, 252 Att, 4 SpDef (0 Speed IVs)
- Heavy Slam
- Fling
- Curse
- Stealth Rock/Dragon Tail/Earthquake
This one's tailor-made to be in a Trick Room team as a late-game physical sweeper. With Iron Ball halving its Speed, along with having its Speed minimized by its nature, 0 IVs, and a use of Curse if it has the chance to set up, it shouldn't be beaten by anything that doesn't have Priority. If something comes in that resists Steel, it could Fling its Iron Ball for pretty decent damage as well. Its final move is either for utility in the for of Stealth Rock or Dragon Tail, or coverage in the form of Earthquake to hit things that resist both Steel and Dark. The downside to this set is that it leaves him especially vulnerable to Low Kick and Grass Knot, but I honestly haven't seen those moves at all in any of my matches on Showdown. Either way, it's wise to bring along something to counter those moves if you plan to use this set.