Kingdra
Skarmory
UU is the tier just below OU. It contains 'mons that are just a little too weak for the highest tier. As a result of power creep, a lot of old mons that were previously OU are now here in UU. If a mon is deemed to powerful for UU, it can get banned with a supermajority commmunity vote. If this vote is successful, then the mon in question will now reside in a sort of limbo between OU and UU called "UUBL". The same 4.5% usage rate rule applies to UU as well. If a mon cannot maintain this usage rate, then it is dropped to Rarely Used