Yanmega

Thanks to Tinted Lens making Yanmega's STAB moves a lot more spammable, it can act as a fantastic Choice Specs wallbreaker against bulkier and slower teams. Yanmega also has access to Speed Boost, which makes it a solid sweeper against frailer offensive teams, which generally don't carry the means to properly deal with it defensively nor offensively. Yanmega's typing is pretty bad defensively, however, as it leaves Yanmega weak to common offensive Fire-, Ice-, Electric-, Rock-, and Flying-types like Salazzle, Mega Abomasnow, Raikou, Rhyperior, and Ninetales. Its typing also gives it a hefty weakness to Stealth Rock, which cuts away 50% of its health upon switching in.