Sableye
Yveltal @ Heavy-Duty Boots
Ability: Dark Aura
EVs: 252 HP / 4 Def / 252 SpD
Calm Nature
- Snarl
- U-turn
- Roost
- Defog
Mega Sableye is worth your time on stall, which is a niche playstyle and not that beginner-friendly so I won't be talking about it here. Definitely not useful on stall with that set. Prankster Pokemon aren't really mandatory or even recommended on any team, but you can use Dual Screens Grimmsnarl on Hyper Offense teams. Your best option for a bulky Dark type is Specially Defensive Yveltal, which checks Calyrex-Shadow and has Defog support.
Blaziken
Necrozma-Dusk Mane @ Rocky Helmet / Leftovers
Ability: Prism Armor
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Sunsteel Strike
- Stealth Rock
- Knock Off / Thunder Wave / Toxic
- Morning Sun / Moonlight
Blaziken is really really bad in NDAG. You're going to want a Stealth Rocker on this team, and Necrozma-DM does that well, checking Zacian-C and having additional utility in Thunder Wave, Knock Off, Toxic, and reliable recovery to boot.
Galvantula
Zekrom @ Leftovers
Ability: Teravolt
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Dragon Dance
- Magnet Rise / Substitute
- Bolt Strike
- Dragon Claw / Outrage
Generally for a Sticky Web user you'd want Smeargle, and for a special attacking Electric type you'd use Arceus-Electric and Regieleki, both of which already are niche picks that aren't really worth your time anywhere other than some sort of Webs team where you want to threaten Defoggers. This is a balance team and not a webs hyper offense, though. Zekrom is a great and pretty splashable Pokemon in the current meta, unlike Arceus-Electric and Regieleki.
Garchomp
Zygarde @ Leftovers
Ability: Power Construct
EVs: 252 HP / 208 Def / 48 Spe
Impish Nature
- Thousand Arrows
- Rest
- Haze / Coil
- Glare
Garchomp is outclassed by Zygarde, who shares its exact typing but has Dragon Dance, Thousand Arrows, and great physical bulk for offensive sets and Haze, Glare, Thousand Arrows, and probably the best physical tanking ability in the meta when transformed. Defensive Zygarde can patch up your team's weakness to Pokemon like Ho-oh, Mega Rayquaza, offensive Necrozma-Dusk Mane, and Primal Groudon.
Zacian-Crowned
Zacian-Crowned @ Rusted Sword
Ability: Intrepid Sword
EVs: 4 HP / 252 Atk / 252 Spe
Adamant Nature
- Behemoth Blade
- Wild Charge
- Sacred Sword --> Close Combat
- Play Rough --> Swords Dance / Crunch / Assurance
There's no reason to use Sacred Sword over Close Combat. You can just switch out to reset the stat drops. Swords Dance, Crunch, and Assurance each provide Zacian a way to potentially get past Necrozma-DM (Assurance is only good when Stealth Rock is up).
Gardevoir
Calyrex-Shadow @ Buginium Z
Ability: As One (Spectrier)
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
- Astral Barrage
- Nasty Plot
- Pollen Puff
- Substitute / Baton Pass
Finally, you have a powerful Special wallbreaker. 2 megas is really bad and Mega Gardevoir itself is terrible. Buginium Z Calyrex-S can beat most Calyrex-S counters with Savage Spin-out.