I created mainly for battles with family and friends, who prefer it as the battling type, but I'm a noob at it since I've always focused on 1v1. The battle type is a 6v6 double battle with no item or sleep clause and a maximum of one uber allowed.
Name: Lucario
Ability: Inner Focus
EVs:
Nature:
Item:
Moves: Crunch, Close Combat, ExtremeSpeed, Ice Punch
Name: Cresselia
Ability: Levitate
EVs:
Nature:
Item:
Moves: Reflect, Light Screen, Moon Light or Toxic, Ice Beam.
Name: Swampert/Empoleon
Ability: Torrent
EVs:
Nature:
Item:
Moves: Earthquake or Grass Knot, Ice Beam, Muddy Water (for Swampert) or Hydro Pump, Protect.
Name: Metagross
Ability: Clear Body
EVs:
Nature:
Item:
Moves: Meteor Mash, Earthquake, Explosion, Thunder Punch.
Name: Rayquaza
Ability: Air Lock
EVs:
Nature:
Item:
Moves: Brick Break, ExtremeSpeed, Draco Meteor, Overheat or Fire Blast.
Name: Togekiss
Ability: Serene Grace
EVs:
Nature:
Item:
Moves: Nasty Plot or Thunder Wave, Roost, Air Slash, Aura Sphere
Final Words:
I read that the Smogon site gives information for 1v1 battles so I'm still looking in to see what Natures, EVs, and Items would be most effective for a double battle. I went with Lucario and Cresselia as my leads due to the usage of Light Screen and Reflect but was originally thinking of using a Metagross, Swampert/Empoleon lead. I was also considering replacing Cresselia with Scrizor if the defense wasn't too helpful in doubles but that would have left a greater weakness to fire types. I removes the usage of Stealth Rock from the team because I didn't think it would play such a huge role in doubles where switching is done less often.

Name: Lucario
Ability: Inner Focus
EVs:
Nature:
Item:
Moves: Crunch, Close Combat, ExtremeSpeed, Ice Punch
Strategy
I chose Lucario because Crunch and Close Combat are good for handling ghost, dark and even psychics who might carry signal beam which could be devastating for my Cresselia attempting to set up Dual Screens. ExtremeSpeed gives it a priority move while Ice Punch can hit dragon leads who may also carry crunch.

Name: Cresselia
Ability: Levitate
EVs:
Nature:
Item:
Moves: Reflect, Light Screen, Moon Light or Toxic, Ice Beam.
Strategy
I make use of Cresselia's defensive capabilities to set up improving the rest of my teams defense. Moonlight provides it a healing move while Ice Beam keeps it from being a simple suicide lead although i could replace Moon Light with Toxic to spread status around but risk having it as a suicide lead. In doubles I'm not sure which would be more effective.


Ability: Torrent
EVs:
Nature:
Item:
Moves: Earthquake or Grass Knot, Ice Beam, Muddy Water (for Swampert) or Hydro Pump, Protect.
Strategy
I was unsure of the decision between Swampert and Empoleon because they are both bulky water types. Earthquake is there in case Lucaio is taken down and wont effect Cresselia or Grass Knot could be used to take on waters. Muddy Water on Swampert provides a good STAB that effects both of my oponents pokemon without causing damage to my team and could be replaced by Hydro Pump on Empoleon. Protect is mainly to stay alive if I use Metagross' Explosion as they will be most likely be out at the same time.

Name: Metagross
Ability: Clear Body
EVs:
Nature:
Item:
Moves: Meteor Mash, Earthquake, Explosion, Thunder Punch.
Strategy
Meteor Mash provides Metagross with a powerful STAB attack. Earthquake can also be used when paired with Cresselia withough effect or with Togekiss in play. Explosion lends it a powerful attack that can be used when paired with Swampert who can Protect against and Thunder Punch is to hit bulky water typed that could wall metagross (excluding Swampert).

Name: Rayquaza
Ability: Air Lock
EVs:
Nature:
Item:
Moves: Brick Break, ExtremeSpeed, Draco Meteor, Overheat or Fire Blast.
Strategy
Rayquaza provides a good attack stat. Brick Break helps work around opposing Light Screen and Reflect set ups as well as having a super effective attack against Blissey. ExtremeSpeed is a priority move to quicky pick off weakened foes and Draco Meteor Provides a STAB attack to heavily damage whatever its up against. The decision between Overheat and Fire Blast is though because both have outstanding power but Fire Blast has a greater chance of missing, Overheat on the other locks Rayqaza into the attack which can then be switched into along with confusing after it is done.

Name: Togekiss
Ability: Serene Grace
EVs:
Nature:
Item:
Moves: Nasty Plot or Thunder Wave, Roost, Air Slash, Aura Sphere
Strategy
Togekiss' Serene Grace paired with Air Slash and Thunder Wave give it a good chance of cripling opponents, especially if they carry a lighthing attack that could cause severe damage, almost limiting my opponent to attack from one Pokemon instead of both while being weared down. Nasty Plot could be used in order to strengthen its Air Slash or Aura Sphere, which would help against Blissey, but I'm unsure of the capabilities of such moves in doubles.
Final Words:
I read that the Smogon site gives information for 1v1 battles so I'm still looking in to see what Natures, EVs, and Items would be most effective for a double battle. I went with Lucario and Cresselia as my leads due to the usage of Light Screen and Reflect but was originally thinking of using a Metagross, Swampert/Empoleon lead. I was also considering replacing Cresselia with Scrizor if the defense wasn't too helpful in doubles but that would have left a greater weakness to fire types. I removes the usage of Stealth Rock from the team because I didn't think it would play such a huge role in doubles where switching is done less often.