Ok I've got a team here that I randomly put together, but it actually works, so I'm going to need your help to improve it.
Lead:
Gengar @ Focus Sash
Ability: Levitate
Evs: 252 Atk/252 Spe/6 HP
Nature: Timid
- Shadow Ball
- HP ICE
- Thunderbolt
- Destiny Bond
I like this Gengar as a lead. I counters Salamences, Gyarados, Yanmegas, and Trick users like Trick Gengars. I can take advantage of a scarf if I get one. HP Ice comes in handy with dragons, and Shadow Ball can hit for massive damage. Destiny Bond is for mid-game things like Blissey if I have low HP, and Tyranitars which counter Gengar.
Metagross @ Leftovers
Ability: Clear Body
EVs: 252 Atk/246 HP/12 Def
Nature: Adamant
- Thunder Punch
- Ice Punch
- Meteor Mash
- Bullet Punch
This Metagross is very effective. Thunder Punch helps against things like Vaporeon, Gyarados, Suicunes, and other waters/flyings. Ice Punch destroys things like Salamence, Dragonite, Roserades, and does well against Zapdos. Meteor Mash is there for STAB and it does a good deal of damage to Bliss. Bullet Punch is there for priority while it still does a fair amount. The leftovers are effective since this Metagross is bulky, and it needs some HP every turn. I invested some EVs in defense just for some better tanking.
Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 Speed/252 SpA/6 HP
Nature: Timid
- Substitute
- Toxic
- Earth Power
- Flamethrower
Lol Scarftrans. They are too easily countered and when this guy gets a sub up, he can toxic or do some nuetral damage. The reason for the max speed and SpA evs are so he still has lots of speed, and good SpA. However, I might want to make him a bit bulkier. Flamethrower for STAB obviously, and Earth Power hits many things in the OU metagame, including Heatran himself.
Dugtrio @ Choice Scarf
Ability: Arena Trap
EVs: 252 Atk/252 Spe/6HP
Nature: Adamant
- Earthquake
- Aerial Ace
- Stone Edge
- Pursuit
Wow. This guy is a good revenge killer. No. The best. He can Pursuit flying types or running levitators, and hits everything hard with an Earthquake. He is a Tran counter, and he kills everything else in his path that is weak to ground, flying, or rock.
Forretress @ Leftovers
Ability: Sturdy
EVs: 252 HP/202 Def/56 Atk
Nature: Relaxed
- Rapid Spin
- Stealth Rock
- Explosion
- Gyro Ball
Forretress is my spinner, spiker, and exploder. He OHKOs Blissey with Explosion, and he takes in T-waves and hits back with Gyro Ball. He completely walls physical attackers like Metagross, and if a Scizor tries to set up, I can switch to my tran for coverage.
Vaporeon @ Leftovers
Ability: Water Absorb
EVs: 188 HP/252 Def /68 SpA
Nature: Bold
- Surf
- HP Electric
- Wish
- Protect
This guy here walls things like Swamperts, and gives them no choice but to switch. He kills Infernapes and can survive a Thunder Punch. HP Electric rapes Gyarados and others. He works well with Heatran, as he absorbs water moves and hits back. Another option is passing his Wish, or Protecting to scout trickers or other Pokemon.
There is my team. I hope you can help me improve it! Thanks.
Lead:

Gengar @ Focus Sash
Ability: Levitate
Evs: 252 Atk/252 Spe/6 HP
Nature: Timid
- Shadow Ball
- HP ICE
- Thunderbolt
- Destiny Bond
I like this Gengar as a lead. I counters Salamences, Gyarados, Yanmegas, and Trick users like Trick Gengars. I can take advantage of a scarf if I get one. HP Ice comes in handy with dragons, and Shadow Ball can hit for massive damage. Destiny Bond is for mid-game things like Blissey if I have low HP, and Tyranitars which counter Gengar.

Metagross @ Leftovers
Ability: Clear Body
EVs: 252 Atk/246 HP/12 Def
Nature: Adamant
- Thunder Punch
- Ice Punch
- Meteor Mash
- Bullet Punch
This Metagross is very effective. Thunder Punch helps against things like Vaporeon, Gyarados, Suicunes, and other waters/flyings. Ice Punch destroys things like Salamence, Dragonite, Roserades, and does well against Zapdos. Meteor Mash is there for STAB and it does a good deal of damage to Bliss. Bullet Punch is there for priority while it still does a fair amount. The leftovers are effective since this Metagross is bulky, and it needs some HP every turn. I invested some EVs in defense just for some better tanking.

Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 Speed/252 SpA/6 HP
Nature: Timid
- Substitute
- Toxic
- Earth Power
- Flamethrower
Lol Scarftrans. They are too easily countered and when this guy gets a sub up, he can toxic or do some nuetral damage. The reason for the max speed and SpA evs are so he still has lots of speed, and good SpA. However, I might want to make him a bit bulkier. Flamethrower for STAB obviously, and Earth Power hits many things in the OU metagame, including Heatran himself.

Dugtrio @ Choice Scarf
Ability: Arena Trap
EVs: 252 Atk/252 Spe/6HP
Nature: Adamant
- Earthquake
- Aerial Ace
- Stone Edge
- Pursuit
Wow. This guy is a good revenge killer. No. The best. He can Pursuit flying types or running levitators, and hits everything hard with an Earthquake. He is a Tran counter, and he kills everything else in his path that is weak to ground, flying, or rock.

Forretress @ Leftovers
Ability: Sturdy
EVs: 252 HP/202 Def/56 Atk
Nature: Relaxed
- Rapid Spin
- Stealth Rock
- Explosion
- Gyro Ball
Forretress is my spinner, spiker, and exploder. He OHKOs Blissey with Explosion, and he takes in T-waves and hits back with Gyro Ball. He completely walls physical attackers like Metagross, and if a Scizor tries to set up, I can switch to my tran for coverage.

Vaporeon @ Leftovers
Ability: Water Absorb
EVs: 188 HP/252 Def /68 SpA
Nature: Bold
- Surf
- HP Electric
- Wish
- Protect
This guy here walls things like Swamperts, and gives them no choice but to switch. He kills Infernapes and can survive a Thunder Punch. HP Electric rapes Gyarados and others. He works well with Heatran, as he absorbs water moves and hits back. Another option is passing his Wish, or Protecting to scout trickers or other Pokemon.
There is my team. I hope you can help me improve it! Thanks.