Drampa  
DNB. It's perfectly understandable why people have such a strong reaction against this mon, given that it dwarfs the power level of the rest of the tier, but atm I don't think we've seen it doing anything particularly unreasonable. It is not too difficult to build a team that can minimize the amount of times Drampa gets a free switchin while having viable checks like Clefairy, Carbink, Wish Togedemaru, AV Perrserker, and random Normal and Fire resists/immunities to prevent Drampa from just "clicking buttons" when it does come in. In other words, the degree to which Drampa actually breaks teams is largely dependent on how good the Drampa user is at getting it in at the right moment and then getting predictions right, which does not strike me as the hallmark of a broken Pokemon. While the payoff is naturally large if you do make the correct calls, Drampa does nothing that a wallbreaker shouldn't be able to do and really is more broken on paper than it is in practice.