Nominations from me: Victini - As many have said simply too hard hitting for the things in the tier to take, with the option of going mixed to allow it to defeat what very few counters it has (not to mention its coverage moves allow it to kill some of them anyway). Kyurem - Again as others have said, ridiculous attacking capacity from both sides and similar to Victini almost no counters. Part of the issue is the danger of two different sets (Specs and Sub) similar to Mence, meaning if you guess wrongly something will die. Chlorophyll - Whilst I know that Drought as is is far too much for UU for the reasons others have posted, I can't help but shake the feeling that it may just be the ability of teams to pack 3 or so Chlorophyllers (some of if not the deadliest sweepers in the tier, as well as having access to Sleep moves to cripple what they cannot beat) in a similar fashion to Rain with Swift Swimmers in OU is what pushes it over the edge, and what makes it broken. Fire move spam is very powerful, but there are several 4x resists and immunes in the tier as well as pokemon like Kingdra who can set up Rain Dance and abuse it viably, as well as a huge amount of pokemon who outspeed every single Fire mon in UU and can revenge the hardest hitters. Banning individual Chlorophyllers is possible, but would require quite probably 6 or more bans in order to remove the best abusers and as such this option at the least allows people to use defensive Tangrowth, etc. Whilst I realise that this probably isn't going to be a popular option, I believe keeping Drought for another round to see how it fares without Chlorophyll (and Victini) is a worthwhile endeavour for the sake of weather diversity - and obviously I believe it would not be broken in this situation.