So starting off from a rain team, I have tried to come up with ways to deal with other current metagame strategies. This is the result, but it's not quite finished so constructive criticism is appreciated.
Arceus-Fighting @Fist Plate
Nature:Timid
EV Spread:
HP:4 - Special Attack:252 - Speed:252
Moves:
Judgment
Magic Coat
Thunder Wave
Recover
This is my lead pokemon. This works as a fantastic lure for Darkrai who will attempt a Dark Void to send it to sleep, but the use of Magic Coat will send it right back taking out one of the most annoying leads in existence. It also is capable of reflecting all stealth hazards, so it is viable against other set-up leads and quite useful against the phazing strategy. Dark Pulse is used to damage psychic types on the switch in. Arceus-Fighting also has great synergy with Wobbuffet, against offensive Mewtwo. An example would be when they send out Mewtwo as the lead I can switch to Wobbuffet to resist the obvious Psystrike, trap and encore it and take it out.
Dialga @Leftovers
Nature:Modest
EV Spread:
HP:252 - Special Attack:56 - Special Defense:200
Moves:
Fire Blast
Roar
Stealth Rock
Draco Meteor
This is my setup and phaze pokemon. The Fire Blast is helpful against pokemon that would resist the Draco Meteor, and even in rain may do a significant chunk to Forretress and Ferrothorn alike. Draco Meteor is used for taking out Palkia and other Dragon types. Even after the Special Attack drop it is still reasonably useful with Roar to inflict hazard damage. The Roar can also be used against Wobbuffet. Due to the typing it can be a useful pivot for attacks of the Electric, Dark and Psychic type.
Giratina-O @Griseous Orb
Nature:Naughty
EV Spread:
Attack:248 - Special Attack:252 - Speed:8
Moves:
Dragon Tail
Shadow Sneak
Draco Meteor
Toxic
This is the classic mixed attacker Giratina-O that provides an excellent synergy with Dialga by covering its weaknesses. Dragon Tail is to phaze through taunt and if they set up a substitute I can switch to Dialga and phaze with him. Toxic is used over will-o-wisp as it can really help to take down Ho-OH which is a direct counter to my Arceus. Speaking of Arceus, it works as a good check to ExtremeKiller Arceus, as it is immune to Extreme Speed and when it goes for the swords dance Giratina can just phaze with Dragon Tail.
Wobbuffet @Custap Berry
Nature:Impish
EV Spread:
HP:252 - Defense:222 - Special Defense:56
Moves:
Counter
Destiny Bond
Mirror Coat
Encore
What can I say this is probably the star of this team. With the Custap Berry it can provide an easy 2 for the price of 1 KO with Destiny Bond. It also can encore any set up pokemon such as Para-dance Groudon and then switch to setup rocks with Dialga. It is capable of butchering any full baton pass team by just encoring it and if I send it out against a trick-room user it can waste a turn or two. It is also a good absorber for paralysis as all of its moves go last anyway. Another use for this Wobbuffet, and in fact all Wobbuffet, is the ability to trap a Weather Inducer. It will deal with all attacks from weather inducers, apart from the Water Spout of a Max HP Kyogre which will KO it, and can inflict 4X super effective damage against a Tyranitar.
Palkia @Haban Berry
Nature:Timid
EV Spread:
Special Attack:252 - Special Defense:4 - Speed:252
Moves:
Fire Blast
Spacial Rend
Thunder
Surf
This is my offensive and defensive lure. Pokemon such as Dialga which would usually one hit-ko with Draco Meteor or Kingdra which would usually revenge kill Palkia are capable of being killed instead. For example two spacial rends will take out the Dialga, while the Draco Meteor will do 86% damage. The Kingdra while it may outspeed will be taken out with a Thunder. Surf is an good choice as in the rain it does huge damage. Thunder will take advantage of rain for 100% accuracy and is a good choice to greatly damage Kyogre. It will survive a rain boosted Water Spout easily and greatly damage the Choice Scarf Kyogre with a Thunder. Fire Blast is used again as I can pretend to be choiced and then destroy Forretress when it switches in on the predicted Spacial Rend.
Kyogre @Leftovers
Nature:Modest
EV Spread:
HP:252 - Special Attack:252 - Speed:4
Moves:
Scald
Ice Beam
Thunder
Calm Mind
The king of Ubers. This set works very well with Encore from Wobbuffet and can then come in itself on certain pokemon and set up with Calm Mind. Ice Beam is to take out Dragon type pokemon and Thunder is used again to take advantage of the rain. I chose scald over Water Spout as I didn't want to have my only water STAB move weakened over the course of the match, and the decent chance of a burn is too much to miss as it will cripple physical attackers.
Arceus-Fighting @Fist Plate
Nature:Timid
EV Spread:
HP:4 - Special Attack:252 - Speed:252
Moves:
Judgment
Magic Coat
Thunder Wave
Recover
This is my lead pokemon. This works as a fantastic lure for Darkrai who will attempt a Dark Void to send it to sleep, but the use of Magic Coat will send it right back taking out one of the most annoying leads in existence. It also is capable of reflecting all stealth hazards, so it is viable against other set-up leads and quite useful against the phazing strategy. Dark Pulse is used to damage psychic types on the switch in. Arceus-Fighting also has great synergy with Wobbuffet, against offensive Mewtwo. An example would be when they send out Mewtwo as the lead I can switch to Wobbuffet to resist the obvious Psystrike, trap and encore it and take it out.
Dialga @Leftovers
Nature:Modest
EV Spread:
HP:252 - Special Attack:56 - Special Defense:200
Moves:
Fire Blast
Roar
Stealth Rock
Draco Meteor
This is my setup and phaze pokemon. The Fire Blast is helpful against pokemon that would resist the Draco Meteor, and even in rain may do a significant chunk to Forretress and Ferrothorn alike. Draco Meteor is used for taking out Palkia and other Dragon types. Even after the Special Attack drop it is still reasonably useful with Roar to inflict hazard damage. The Roar can also be used against Wobbuffet. Due to the typing it can be a useful pivot for attacks of the Electric, Dark and Psychic type.
Giratina-O @Griseous Orb
Nature:Naughty
EV Spread:
Attack:248 - Special Attack:252 - Speed:8
Moves:
Dragon Tail
Shadow Sneak
Draco Meteor
Toxic
This is the classic mixed attacker Giratina-O that provides an excellent synergy with Dialga by covering its weaknesses. Dragon Tail is to phaze through taunt and if they set up a substitute I can switch to Dialga and phaze with him. Toxic is used over will-o-wisp as it can really help to take down Ho-OH which is a direct counter to my Arceus. Speaking of Arceus, it works as a good check to ExtremeKiller Arceus, as it is immune to Extreme Speed and when it goes for the swords dance Giratina can just phaze with Dragon Tail.
Wobbuffet @Custap Berry
Nature:Impish
EV Spread:
HP:252 - Defense:222 - Special Defense:56
Moves:
Counter
Destiny Bond
Mirror Coat
Encore
What can I say this is probably the star of this team. With the Custap Berry it can provide an easy 2 for the price of 1 KO with Destiny Bond. It also can encore any set up pokemon such as Para-dance Groudon and then switch to setup rocks with Dialga. It is capable of butchering any full baton pass team by just encoring it and if I send it out against a trick-room user it can waste a turn or two. It is also a good absorber for paralysis as all of its moves go last anyway. Another use for this Wobbuffet, and in fact all Wobbuffet, is the ability to trap a Weather Inducer. It will deal with all attacks from weather inducers, apart from the Water Spout of a Max HP Kyogre which will KO it, and can inflict 4X super effective damage against a Tyranitar.
Palkia @Haban Berry
Nature:Timid
EV Spread:
Special Attack:252 - Special Defense:4 - Speed:252
Moves:
Fire Blast
Spacial Rend
Thunder
Surf
This is my offensive and defensive lure. Pokemon such as Dialga which would usually one hit-ko with Draco Meteor or Kingdra which would usually revenge kill Palkia are capable of being killed instead. For example two spacial rends will take out the Dialga, while the Draco Meteor will do 86% damage. The Kingdra while it may outspeed will be taken out with a Thunder. Surf is an good choice as in the rain it does huge damage. Thunder will take advantage of rain for 100% accuracy and is a good choice to greatly damage Kyogre. It will survive a rain boosted Water Spout easily and greatly damage the Choice Scarf Kyogre with a Thunder. Fire Blast is used again as I can pretend to be choiced and then destroy Forretress when it switches in on the predicted Spacial Rend.
Kyogre @Leftovers
Nature:Modest
EV Spread:
HP:252 - Special Attack:252 - Speed:4
Moves:
Scald
Ice Beam
Thunder
Calm Mind
The king of Ubers. This set works very well with Encore from Wobbuffet and can then come in itself on certain pokemon and set up with Calm Mind. Ice Beam is to take out Dragon type pokemon and Thunder is used again to take advantage of the rain. I chose scald over Water Spout as I didn't want to have my only water STAB move weakened over the course of the match, and the decent chance of a burn is too much to miss as it will cripple physical attackers.