Normal Arceus and Lugia are done.
Reserving
Ghost Arceus and
Fire Arceus next. They will be done later.
Ghost Arceus
Ghost
Base Stats: 120 HP / 120 Atk / 120 Def / 120 SpA / 120 SpD / 120 Spe
Ability: Multitype
One of the most versatile Arceus formes, Ghost Arceus can do just about anything. It can abuse Swords Dance alongside Shadow Force, Shadow Claw, Brick Break, and/or ExtremeSpeed to become a frightening physical sweeper, or it can use Calm Mind, Judgment, Focus Blast, and Recover to become a potent, almost unkillable special sweeper. Ghost Arceus can gain perfect neutral coverage on both sides of the spectrum, which, combined with its exceptional all around stats, is both very powerful and very hard to take down. Ghost Arceus can also work as a great lead, utilizing its great bulk to beat most other leads one on one while setting up Stealth Rock. Ghost Arceus can also use Magic Coat to stop other hazard leads from setting up on it. Ghost Arceus also works very well as a defensive spinblocker with access to support moves such as Will-O-Wisp, Thunder Wave, Toxic, Roar, and Perish Song.
Fire Arceus
Fire
Base Stats: 120 HP / 120 Atk / 120 Def / 120 SpA / 120 SpD / 120 Spe
Ability: Multitype
Fire Arceus isn't quite as versatile or defensively sound as the other Arceus formes, but it makes up for it with sheer offensive might. Fire Arceus' STAB Judgment or Fire Blast can rip severe holes into most Pokemon in the sunlight, and combined with Calm Mind, Recover, and Arceus' awesome bulk, it can easily set up for a devastating incendiary rampage. Arceus can also utilize Thunder to destroy the Kyogre that dare come in to change the weather. Although quite a few things in Ubers resist the Fire/Electric attacking combination, such as Reshiram, Giratina, Latias, and Zekrom, Fire Arceus' bulk and base 120 Speed allow it to actually use them as set up bait. (Save Zekrom of course, but a swift Spacial Rend easily takes it out.) Although it faces some compoetition from newcomer Reshiram, Fire Arceus is significantly faster and bulkiers, has access to Electric-type attacks to help deal with Water-types, and has access to Recover.
EDIT- Reserving
Steel Arceus.
Steel Arceus
Steel
Base Stats: 120 HP / 120 Atk / 120 Def / 120 SpA / 120 SpD / 120 Spe
Ability: Multitype
Steel Arceus is one of the most resilient Arceus formes. Its typing grants it resistances to many common attack types in the Ubers enviroment, including Dragon-, Ghost-, Dark-, and Ice-type attacks. Steel Arceus can easily take advantage of its brilliant defensive stats, Speed, and Recover to Calm Mind against the majority of foes, even being able to outlast Fire-types if it is raining. Although STAB Steel-type attacks don't offer much in the way coverage, Steel Arceus is usually able to garner so many Calm Mind boosts that it usually won't matter, although if needed, it can use Thunder to strike at the majority of Steel-type resistant Pokemon such as Kyogre. Steel Arceus can also use Roar alongside Calm Mind to stop other Calm Minders from setting up on alongside it, making it even more difficult to take down without incredibly powerful attacks. Steel Arceus' defenses even allow it to sweep well with Swords Dance along with Iron Head for reliable STAB, although that set's coverage leaves something to be desired.