Kingdra

Kingdra's stats may make it seem like it's outclassed by Dragon-types such as Palkia and Rayquaza. However, Kingdra's ability, Swift Swim, puts it in a class of its own. With Kyogre's eternal rain, Kingdra becomes an excellent revenge killer, and either a powerful mixed attacker, or a sweeper that is incredibly difficult to revenge kill. In the rain, Kingdra will outspeed even Choice Scarf Garchomp and Choice Scarf Palkia, and will easily OHKO both with its powerful, STAB Dragon-type attacks. No other Dragon-type is capable of doing this in Ubers, often making Kingdra a deadly surprise for most teams that rely on Choice Scarfed Dragon-type Pokemon to stop sweeps from Rayquaza. Overall, Kingdra is an excellent Pokemon in Ubers, and is the prime candidate to base an Uber rain team around.