Necrozma
Regular Necrozma is terrible, outclassed by Mewtwo and of course, Dusk Mane Necrozma.
Necrozma-DM @ Leftovers / Rocky Helmet
Ability: Prism Armor
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature (+Def -SpA)
- Sunsteel Strike
- Morning Sun
- Stealth Rock
- Toxic / Knock Off
Darkrai
It's just bad. Way too inconsistent. Yveltal is a much better Dark type and is the best Dynamaxer in the franchise.
Yveltal @ Life Orb
Ability: Dark Aura
EVs: 252 SpA / 252 Spe / 4 HP
Modest Nature (+SpA -Atk)
- Dark Pulse
- Oblivion Wing
- Heat Wave
- Focus Blast
Arceus-Ground
Gravity is a gimmick move that is only good at supporting Darkrai, which is much worse than Yveltal. It's a wasted moveslot. Replace it with Recover or a coverage move
Orbeetle
Don't use Orbeetle in Nat Dex AG if you want to win. It's pretty much useless, there are Pokemon that can do its job better. You can replace it with an offensive Pokemon like Primal Groudon, Xerneas, Zacian-Crowned, or Calyrex-Shadow.
Mega Beedrill
There is absolutely no reason to use Mega Beedrill in Nat Dex AG. It wastes the Mega slot of Rayquaza, a far superior Mega evolution. It's stronger (if holding a boosting item), has a bigger movepool, and much, much bulkier. It can cancel out the weather summoned by Primal Groudon, Tyranitar, Kyogre, and Primal Kyogre.
Rayquaza-Mega @ Life Orb
Ability: Delta Stream
EVs: 252 Atk / 4 Def / 252 Spe
Adamant / Jolly Nature (+Atk -SpA /+Spe -SpA)
- Dragon Descent
- Extreme Speed
- V-create
- Earthquake / Dragon Dance
Zekrom
The Substitute + Dragon Dance set is usually better.
Zekrom @ Lum Berry / Leftovers
Ability: Teravolt
EVs: 252 Atk / 252 Spe / 4 HP
Jolly Nature (+Spe -SpA)
- Bolt Strike
- Outrage
- Substitute
- Dragon Dance