Scizor

Mega Scizor's brilliant Bug / Steel typing and excellent mixed bulk allow it to handle notable offensive threats in 1v1 including Mega Metagross, Kartana, Magearna, and Meloetta. Access to Iron Defense and reliable recovery in Roost lets it beat most physical setup sweepers that can't 2HKO it, including Swords Dance Mega Mawile and Landorus-T, Dragon Dance Dragonite, and non-Taunt Mega Gyarados. Mega Scizor's moveset also gives it a very high PP count, allowing it to outstall certain defensive Pokemon like non-Hidden Power Fire Mega Venusaur, Mega Aggron, and Porygon2. However, Mega Scizor's glaring 4x weakness to Fire means that it is easily beaten by Fire-type Pokemon like Mega Charizard X, Mega Charizard Y, and Heatran. Furthermore, this weakness is exploited by threats like Kommo-o, Naganadel, and Necrozma that carry Fire-type coverage. Mega Scizor competes with other tanky Steel-types like Magearna, Mega Metagross, Mega Mawile, and Aegislash, which give up a neutrality to Ground for a reduced weakness to Fire that lets them handle foes with Fire-type coverage more reliably and have greater offensive presence and access to a wider variety of coverage moves. Registeel, in particular, gives Mega Scizor stiff competition as a stall Pokemon. It similarly has a Double Dance set, access to recovery in Rest, and the ability to PP stall defensive Pokemon; however, it also sports superior defensive stats and the ability to hold Leftovers. Mega Scizor should mainly be considered over Registeel for its ability to handle Ground- and Fighting-types in addition to the range of Pokemon that are handled by Steel-types.