Registeel

Registeel's bulk lets it easily wall many specially offensive Pokemon in the tier like Diancie, Shaymin, and Swellow while serving as a blanket check to many Pokemon that can only hit it neutrally, especially with special attacks. This, in tandem with access to helpful utility moves such as Stealth Rock, also allows it to be a very consistent entry hazard setter. Registeel can also cripple opposing Pokemon with status without ever being overly passive, as it can stall with Protect and Toxic and deal solid damage with Seismic Toss. On the other hand, its typing means that it is weak to the ever-common Ground-, Fire-, and Fighting-types, specifically being pressured by Salazzle and Zygarde-10% with their super effective STAB moves. In addition, it is susceptible to Taunt, which makes it susceptible to Pokemon like Noivern and Mismagius.