Veigar CoL (reduce Q cost a bit)
Veigar has some pretty serious mana problems early game. He could use some love with a lowered mana cost on Q since you have to spam it a lot to farm AP. Maybe give some mana back on a kill so that you can farm better with it but will cost a lot more if you harass instead.
EDIT: Title was supposed to be QoL... oops.