Ampharos @ Leftovers
Quiet Nature (+Sp. Atk, -Spd)
Trait: Static
~ Thunderbolt
~ Substitute / Signal Beam
~ Focus Punch / Focus Blast
~ Light Screen / Reflect / Thunder Wave
Simple strategy. Hit stuff hard with your two attacks. Substitute and Focus Punch go well together, but if you don't want to use them then you can use Signal Beam and Focus Blast instead. Modest nature if you opt to use those special attacks. The last slot can be used to support your team, whether by setting up a protective screen or paralyzing things to KILL their Speed.
Weavile @ Life Orb / Expert Belt
Jolly Nature (+Spd, -Sp. Atk)
Trait: Pressure
~ Swords Dance
~ Ice Punch
~ Night Slash
~ Brick Break
Pretty standard Swords Dance Weavile. Don't use Avalanche since it has negative priority - meaning you will ALWAYS move last if you use it. This is a bad idea since Weavile is fragile. Dark Pulse is horrible move on Weavile - look at its Special Attack stat! >_> Metal Claw gets horrible coverage and is outclassed in every possible way by Brick Break. If you really want to go offensive, you can use Choice Band and slap Ice Shard over Swords Dance.
Gyarados @ Leftovers / Life Orb
Adamant Nature (+Atk, -Sp. Atk)
Trait: Intimidate
~ Dragon Dance
~ Waterfall
~ Earthquake
~ Ice Fang / Stone Edge
Such a beast. Don't use special moves on Gyarados. Anyways, you Dragon Dance a few times and then kill everything in sight with your attacks. Pretty simple. Either way, Dragon Rage and Twister are horrible attacks that do negligible damage. Never use them.
Garchomp @ Life Orb
Jolly Nature (+Spd, -Sp. Atk)
Trait: Sand Veil
~ Earthquake
~ Dragon Claw / Outrage
~ Fire Fang
~ Stone Edge / Swords Dance
Kills stuff, 'nuff said.
Charizard @ Expert Belt / Life Orb / Wise Glasses / Choice Specs
Timid Nature (+Spd, -Atk)
Trait: Blaze
~ Flamethrower
~ Air Slash
~ Focus Blast
~ Dragon Pulse / Overheat
Great coverage. If you want to use Fly, then use it with Dragon Dance or Swords Dance on a physical set. Still, it's probably best to leave HMs to Pelipper, who can take care of all your Surf and Fly needs. Blast Burn is also not a good idea since it leaves you helpless after you use it. Flamethrower is a much more reliable choice.
Lucario @ Life Orb
Rash Nature (+Sp. Atk, -Sp. Def)
Trait: Steadfast
~ Aura Sphere
~ Dark Pulse / Shadow Ball
~ Psychic
~ Extremespeed / Close Combat
Yet another sweeper. Extremespeed or Close Combat to hit Pokemon like Blissey who will withstand your Special Attacks with ease. Again, Steel is a horrible attacking type, so Metal Claw is a bad option. Bone Rush is lol at best, with bad accuracy and weak power.
If there is a problem with this team, it's that there are too many fragile sweepers. Luckily, Gyarados and Garchomp hold their own in any situation, but Weavile, Charizard, and Lucario all die fairly easily. Still, this is ingame, where might makes right, so perhaps it is alright to have a team full of sweepers.