Which champions are broken in ARAM, featured game modes, and Twisted Treeline?

For example, is really broken in ARAM. He can waveclear, poke, has decent sustained damage, but the main thing about him is that he can kill towers really fast, and ARAM has even fewer towers to work with. There is a reason why he has a 70% winrate in ARAM.

is broken in OVERCHARGE, since the map is narrow and full of walls to which she can condemn you to, and she is a really good duelist for an ADC.

are broken in Definitely not Dominion because it is almost impossible to capture a point they are defending.

Old was really broken in Hexakill Twisted Treeline because she could get easy resets with so many players on this map and they are all standing close to each other, so she could easily deal tons of AoE damage. Not sure about new Kat.

is broken on URF because her Q has a very low cooldown and she can easily proc vitals due to that, and then do tons of damage while healing over the top despite the fact that healing is reduced on this game mode. Because it is true damage based on a percentage of the max health, no one is safe from it, and on top of that, trying to CC her is almost impossible because Riposte has a very low cooldown too.