Durant @ Choice Band
Ability: Hustle
EVs: 252 Spd / 252 Atk / 4 HP
Jolly Nature
- X-Scissor
- Iron Head
- Superpower
- Rock Slide
Not much to say here, but this guy takes care of most of the Pokemon that Molk mentioned, with the exception of Sceptile (which is rarer than the other stuff that was mentioned). While it does have issues switching into them, it KOs CM Cress and CM Reuniclus (not Trick Room though, but we are better off against those than the CM variants) along with Mega Aboma and Virizion. It's also in general a strong Pokemon that doesn't require set up, something we honestly don't have much of right now.
I chose CB Durant over HC Durant because you need CB to OHKO Virizion after Stealth Rock, plus Hone Claws Durant would be slightly redundant with Cobalion imo.