Xayah and rakan
Before you suck their dicks and say I'm bronze and "lol git gud" Understand these champions are fucking awesome...and then understand these champions are fucking cancer.
If they are picked together which...they almost ALWAYS are. They are unbeatable. End of the fucking discussion. Don't argue you can outplay them, I won't hear it. You can't. You didn't beat them, and I will never believe you beat them ever.
TOGETHER they are overpowered and unstopable, seperate they are just great champions with pretty nice kits.
Xayah is finally an adc who doesn't get 1v1'd by literally everyone, Rakan is just a pain in the ass support who peels and then walks away bming you.
Xayah's E is just...it's just so broken holy shit the amount of damage, if you don't 1 shot kill her, and thanks to her ult...you won't. She is going to take out your entire team in 1-2 attacks. I don't really see a counterplay to her, but maybe that's because I will ban her each and every draft/ranked game I see. If I can't ban her lee sin is next up.
Her ult is nice but a bit too powerful, it lets her jump up and throw massive damaging feathers like an upgraded fizz E on crack. But I like the ability to be alive more than 3 seconds as an adc.
Rakan is a huge pain in the ass with his leap going over walls, his insane speed with that charm. He's a melee ahri minus the damage.
Idk how to close off a rant, I think they're awesome but if you don't ban at least one your game is going south fast. I don't really know any counterplay to xayah atm aside from insane burts