Draven or Kog' Maw

Depends on your style as an adc. If you like just passively farming and not going for all ins but maybe a little poke during laning go for kog. He excels in late game teamfights when protected by a team, absolutely shredding tanks with mixed damage and % health. I'd recommend him for premade games. If you like going for all in fights with burst damage and committing it all for that one kill go for Draven. The axe mechanic can be tricky but when you get that first kill and deposit a decent amount of stacks you can start to snowball out of control. He's decent at all stages of the game but struggles against consistent cc (even soft cc) and hyper tanks but does well against squishy burst targets like the enemy adc and sometimes even assassins. I'd recommend him for solo queue over kog.

DRAAAVEN. once you get your first ill its game over.

Kog is more squishy but reliable, draven takes alot of skill to play, his axes can be funny to use also.