Mamoswine

Although Mamoswine lost a small niche in this year's VGC format without genies to KO, there are still many reasons to use this friendly mammoth. First and foremost, it is still the epitome of an anti-metagame Pokemon. Mamoswine has a superb base 130 Attack stat and an excellent offensive typing, with Ice-type STAB moves such as Icicle Crash being capable of OHKOing Amoonguss and Ice Shard being capable of OHKOing uninvested Garchomp and Salamence without Intimidate. In addition, it has an incredibly strong Earthquake that rips through Steel-types such as Aegislash and Mega Mawile, as well as Tyranitar. Mamoswine also has a nifty Electric immunity, and its ability, Thick Fat, gives it extra bulk to survive Fire-type attacks not boosted by STAB, such as Mega Manectric's Overheat. However, Mamoswine is still fairly slow at base 80 Speed, and with a low Special Defense, it is easily KOed by both Mega Charizard Y and Rotom-W, two very common Pokemon in the metagame. Finally, it is vulnerable to priority moves such as Conkeldurr's Mach Punch, Scizor's Bullet Punch, and to a lesser extent, Talonflame's Brave Bird.