From: DonutDeity
If you want to do crit damage, be Trynd. He crits for 1k+ lategame easily, with a 95%ish crit rate.
Sion can do the same and he's easier to farm with if played as AP early game and morphing into AD. Though his crit rate generally rolls around the 70% mark instead, but he has massive lifesteal and a stun. I've gotten Corki to hit for around 1600 late game (longest match I've ever had).
---
Set signature in options page.