Eternal Dialga
Steel/Dragon
100/120/160/170/140/90
Ability: Time Dilation
All moves used by Dialga and its allies don't have to charge/recharge. Moves used by the opponent(s) take twice as long to charge/recharge. Two Dialgas cancel each other out.
New Move: Time Travel
Dragon, Status, -10 priority, 5 PP
Dialga rewinds back to the start of the turn and can choose a move other than Time Travel. Enemies and Dialga's allies use the same move they used the first time the turn happened. RNG elements stay the same.
Infinite Palkia
Water/Dragon
90/120/140/170/160/100
Ability: Space Constriction
For the user and any allies on the field, all non-OHKO moves have perfect accuracy. For the opponent(s), all moves have a doubled chance to miss. Two Palkias cancel each other out.
New Move: Space Shift
Dragon, Status, 10 PP
Palkia teleports the combatants to a field where the weather and terrain are the most beneficial to Palkia and its allies, based on adding up the number of mons on its team with moves boosted by weather and terrains, how many have terrain abilities, how many aren't hindered by certain weathers/terrains, etc. Trick Room is also set if Palkia's team is slower on average.
Distorted Giratina
Ghost/Dragon
150/135/135/135/135/90
Ability: Mutual Annihilation
Causes all types to become weak to themselves.
New Move: Antimatter Beam
Dragon, Special, 100 BP, 100 Acc, 15 PP
This move is super effective against all opponents.
Creator Arceus
Normal
255/255/255/255/255/255
Ability: Omnitype
Arceus will change type to get STAB on any move it uses. It also changes type before getting hit to either be immune or 4x resistant to every move.
New Move: Smite
Normal, Special, 150 BP, 100 Acc, 5 PP
This move's type and whether it's physical or special is determined by which would do the most damage, taking weaknesses, stat boosts, and field conditions into account.
I know this is all busted as fuck, but that's the point.