Registeel

Registeel's viability stems from its immense bulk coupled with its excellent defensive typing, providing it with the defensive capacity to withstand attacks from many of the top-tier threats of the 1v1 metagame between Pokemon like non-Choice Band Dragonite, Choice Specs Greninja, Mega Metagross, non-Nasty Plot Porygon-Z, and Primarina. Moves that boost either of Registeel's defenses allow it to keep up with or even outpace many of the common Pokemon that utilize their own setup moves like Magearna, Tapu Lele, non-Choice Band Zeraora, and Togekiss. The raw PP of all of Registeel's moves even gives it an advantage against other stall Pokemon, such as Mega Slowbro, non-Taunt Mega Sableye, Mega Venusaur, and Type: Null, as it will survive long enough to eventually force the foe to knock itself out by using Struggle. Unfortunately, as a stall-oriented Pokemon, Registeel faces issues against Taunt users like Mega Gyarados, Torrent Greninja, Kommo-o, and Tapu Fini that block it from setting it up and healing off damage. Additionally, as a Steel-type, Registeel faces severe weaknesses to the common and powerful offensive types of Fire, Ground, and Fighting, which are utilized by prevalent threats like Mega Charizard X and Y, Zygarde, Landorus-T, Victini, Mega Lopunny, and Pheromosa.