anyone who doesn't have to root themselves to dish out damage (veigar is very much a stationary target killer), anyone with a spellshield. if the veigar is bad he'll push, and is extremely vulnerable to jungle ganks.

I will suggest the 3 main mids I use.

1.Kassadin is pretty good against him due to his Q which silences, he also bursts a lot, can bait/dodge stun with his ult, etc.
2. Talon. Veigar is trying to stun? E-Q-W-R ignite = dead. Extreme burst. 60 sec CD on ult and builds AD.
3.Galio. It's extremely easy to farm with Q-E, you build MR (survivability)and still get damage, W before a trade, etc.