Well, your main set ups in UU and OU are Bronzong, Ferrothorn, Skamory and Forretress. All of them are slow and weak to fire types. If you want to sweep up, go for Heatran w/ Air Balloon. It will be able to deal with Mamoswine as well (unless it has Thick Fat).
Heatran @ Air Balloon
Ability: Flash Fire
EVs: 252 Sp. Atk, 252 Speed
Nature: Timid
- Fire Blast
- Earth Power
- Hp Ice
- Stealth Rock
Other options:
Espeon/ Xatu with Magic Bounce ability.
Espeon @ Light Clay
Ability: Magic Bounce
EVs: 252 HP, 252 Speed, 4 Def
Nature: Timid
- Reflect
- Light Screen
- Psychic
- HP Fire
Xatu @ Leftovers
Ability: Magic Bounce
EVs: 252 HP, 252 Sp. Def, 4 Speed
Nature: Calm
- Roost
- U-Turn
- Psychic
- Thunder Wave
Sableye/ Whimsicott with Prankster ability & Taunt.
(I won't give a Sableye moveset because Scizornician already gave one; except note that 120 EVs should be in defence, not attack)
Whimsicott @ Leftovers
Ability: Prankster
EVs: 252 HP, 252 Def, 4 Sp. Def
Nature: Bold
- Substitute
- U-Turn/ Encore/ Stun Spore
- Taunt
- Leech Seed
Whimiscott has the benefit of being immune to Leech Seed.