Jirachi @ Leftovers  
Ability: Serene Grace  
Shiny: Yes  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
- Moonblast  
- Iron Head  
- Calm Mind  
- U-turn  

Gardevoir @ Choice Scarf  
Ability: Trace  
Shiny: Yes  
EVs: 252 SpA / 4 SpD / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Moonblast  
- Psychic  
- Mystical Fire  
- Trick  

Heracross @ Leftovers  
Ability: Moxie  
Shiny: Yes  
EVs: 252 Atk / 4 SpD / 252 Spe  
Adamant Nature  
- Close Combat  
- Megahorn  
- Knock Off  
- Spikes  

Ninetales-Alola @ Light Clay  
Ability: Snow Warning  
Shiny: Yes  
EVs: 252 HP / 4 SpA / 252 Spe  
Timid Nature  
IVs: 0 Atk  
- Aurora Veil  
- Freeze-Dry  
- Hail  
- Hypnosis  

Clefable @ Leftovers  
Ability: Magic Guard  
Shiny: Yes  
EVs: 252 HP / 4 Def / 252 SpD  
Calm Nature  
IVs: 0 Atk  
- Teleport  
- Moonblast  
- Wish  
- Protect  

Sandslash-Alola @ Choice Band  
Ability: Slush Rush  
Shiny: Yes  
EVs: 252 Atk / 4 SpD / 252 Spe  
Jolly Nature  
- Iron Head  
- Icicle Crash  
- Brick Break  
- Poison Jab  

252 SpA Gardevoir Moonblast vs. 0 HP / 4 SpD Dragapult: 380-450 (119.8 - 141.9%) -- guaranteed OHKO

252 SpA Gardevoir Mystical Fire vs. 0 HP / 0 SpD Aegislash-Blade: 276-326 (105.7 - 124.9%) -- guaranteed OHKO
you die to banded shadow sneak though but you live scarf ss so that's something to keep in mind. veil helps a ton though

252+ Atk Aegislash-Blade Shadow Sneak vs. 0 HP / 0 Def Gardevoir: 218-258 (78.7 - 93.1%) -- guaranteed 2HKO

252+ Atk Heracross Knock Off (97.5 BP) vs. 0 HP / 0 Def Dragapult: 286-338 (90.2 - 106.6%) -- 37.5% chance to OHKO

I calced a bunch of other one's but I forgot to write them down lol. Feel free to change whatever. I mainly play gen 5 ou and I've been trying out gen 3 ou but I just had some ideas lol.