Don't pick an AD champion against Veigar just because his ult does damage based on your AP
Many people see his ult doing damage based on the enemy's AP and then think: "Veigar is hard countered by AD champions"
Then they instalock 
- I would mention 
too, but he is rarely picked and those who pick him generally are good with him. Same for 
Of course, if you are good with Yasuo/Zed/Talon, and your team needs an AD assassin that can deal not only with Veigar, but also with the rest of their team, then go ahead and pick them.
The problem is that many times those people don't know how to properly play those AD champions and end up feeding. And even when they know how to play those AD champions, sometimes they are not a good choice for the team. Either because they fall off late game, or because the team needs an AP champion so that the enemy tank does not have an easy time itemizing against our team.
Also, Veigar usually ends up one-shotting anyone late game no matter if they are AD or AP. The only champions that he can't one shot are AD bruisers and tanks, and that's because they have the HP and magic resistance needed to survive Veigar's combo.
Pro tip: Veigar isn't necessarily countered by AD champions. You can also counter him with AP champions that can outrange him. Examples include 
. There is also 
which despite being AP, can counter Veigar because he can become untargetable with his Playful/Trickster and avoid Veigar's ult. You can also build AD Fizz and thus counter Veigar even more, but be wary if that's what your team needs. I've also had success countering Veigar with 
because he can use the Sanguine Pool to avoid Veigar's ult and has enough HP to survive the rest of his burst.
Also, every AP champion can buy a 
. This item can counter Veigar because you can activate it at the moment that Veigar's ult is about to hit you. And because you become untargetable, you become immune to his ult, which will go into full cooldown.
.
snowball the lead of his team so Talon can't even burst down the ADC because of how far ahead they are.
and 
, just remember to ask jungle or top to go AP.
, which is understandable on a lot of champions, just build as much MR as you reasonably can into your normal build path. Grab a 
if you really need the Grievous Wounds but otherwise 
gives magic resist and a stronger mana sustain which you can use to abuse Veigar. 
, 
, or heaven forbid 
and watch Veigar scramble to set up for his combo. Banshees breaks any flow he has with combo-ing abilities, Abyssal is both a strong AP item and provides good magic resist and a nice debuff, and the Banner active is incredible against Veigar since he just doesn't have any means of dealing damage to the empowered minion.
into 
mid since ad and high HP = bad time for 
while his high tank stats means i can itemize for anything and still do large ammounts of dmg.
. Sure when I hit my late game hyperscaling you very well may 1 shot me...to bad I tend to hit that by like 20 minutes with a 3-5 level advantage over you because you can't do anything of relevance to me in the early game. The amount of times I kill Veiger at level 2 with Cassio is out right cruel and the combination of Cleanse+Hourglass means I am always ready to negate your ult.
