Standard Mega Scizor (Scizor-Mega) @ Scizorite  
Ability: Technician  
Level: 50  
EVs: 252 HP / 76 Atk / 100 Def / 76 SpD / 4 Spe  
Adamant Nature  
- Bullet Punch  
- Swords Dance  
- Roost  
- Knock Off / uturn 
Bullet punch always kos non bulky mimikyu, +2 bp kos naga after rocks, kos koko 93.8% of the time after rocks, lives +1 mega mence DE, lives torrent boosted hydro cannon

More Spdef Scizor (Scizor-Mega) @ Scizorite  
Ability: Technician  
Level: 50  
EVs: 236 HP / 76 Atk / 52 Def / 140 SpD / 4 Spe  
Adamant Nature  
- Bullet Punch  
- Swords Dance  
- Roost  
- Knock Off / uturn 
More spdef spread basically to live two shadow balls from mega gengar

Speedy Scizor (Scizor-Mega) @ Scizorite  
Ability: Technician  
Level: 50  
EVs: 252 HP / 148 Atk / 108 Spe  
Adamant Nature  
- Swords Dance  
- Bullet Punch  
- U-turn  
- Roost  
Max HP, speed is to outspeed 12 speed Rotom-Heat and get off faster uturns

Offensive Scizor (Scizor-Mega) @ Scizorite  
Ability: Technician  
Level: 50  
EVs: 252 HP / 252 Atk / 4 Spe  
Adamant Nature  
- Swords Dance  
- Bullet Punch  
- Roost  
- Knock Off / superpower 
There are a few variants with slight changes to speed, but basically max attack for power