Swellow

With fantastic Speed, solid Attack, and a great ability, Swellow makes its mark in RU as one of the premier late-game sweepers in the tier. Swellow's gives it the edge against Pokemon such as Sceptile, Choice Scarf Emboar, and Cinccino, three big threats in RU that few other Pokemon can claim to outspeed. Swellow also has a great ability in Guts, which boosts its decent Attack to very high levels when afflicted with a status condition. Two high-powered STAB moves and priority in Quick Attack only augment this firepower and cleaning ability, making it quite difficult to stop Swellow with sheer bulk or Speed once it gets going.

In spite of all of these good qualities, Swellow has next to no coverage against the numerous Rock- and Steel-type Pokemon in RU. It doesn't help that Steelix and Rhydon are two of the premier physical walls in the tier, as both can handle Swellow without much difficulty. With paltry defenses, a weakness to Stealth Rock, the use of a Toxic Orb to activate Guts, and recoil from possible Brave Birds, Swellow's lifespan is very short and generally relegates it to the late-game sweeping role. In spite of this, Swellow is very good at what it does and makes for a great a late-game cleaner with the right support.