I lead with Electivire and Rotom-F
Item: Air-balloon
Ability: Motor-drive
Nature: Adamant
EVs: 252 Attack, 252 Speed, 6 Hp
Thunder-punch: STAB
Ice-punch: Coverage
Earthquake: Coverage+Multiple-Pokemon hit
Rock-slide: Coverage+Multiple-foe hit
My Physical sweeper, pairs really well with Rotom-F.
Item: Leftovers
Ability: Levitate
Nature: Timid
EVs: 252 S.Attack, 252 Speed, 6 Hp
Blizzard: STAB+Multiple-Foe hit
Discharge: STAB+Multiple-Pokemon hit
Hex: Makes use of the high chance that a foe will have a status condition
Light-screen/Reflect: Team support
Special-sweeper, great coverage, immune to E-quake, boosts Electivire's speed.
Item: Evolite
Ability: Prankster
Nature: Bold
EVs: 252 Defense, 252 S.Defense, 6 Hp
Quash: Makes a dangerous opponent go last
Tailwind: Support
Night-shade: Damage
Roost: Healing
A support Pokemon.
Item: Focus-sash
Ability: Intimidate
Nature: Jolly
EVs: 252 Attack, 252 Speed, 6 Hp
Helping-hand: Support
Extreme-speed: Priority
Flare-blitz: STAB
Close-combat: Coverage
(Credit to trachy for set) Physical Sweeper and support Pokemon, Intimidate Cripples Physical Pokemon.
Item: Focus-sash
Ability: Pressure
Nature: Jolly
EVs: 252 Attack, 252 Speed, 6 Hp
Rock-slide: STAB+Multiple Pokemon hit
Earthquake: Coverage
Iron-head: Flinch
Crunch: Coverage
Physical Flinch Sweeper.
Item: Leftovers
Ability: Serene-grace
Nature: Timid
EVs: 252 S.Attack, 252 Speed, 6 Hp
Air-slash: STAB+Flinch
Aura-sphere: Coverage
Psyshock: Coverage
Heal-bell/Reflect/Light-screen: Team-support
I do not usually do double battles. All I know is that the First Combo is good because I did a 6-0 sweep with them easily.