I`ll have to dissagree a bit =] As I often play Swain I could easily own Katarina but on the other hand Catlyn is just terrible. I believe she`s the one who can beat the hell out of Swain as he can barely touch her =[

Probably because you are decent with Swain. Katarina is able to easily dodge his snare and has a healing reduction ability so is a natural counter. I didn't include AD carries because most of the time they are bot with the support.

i main veigar since the game released.

Morgana is beateble with veigar, most rush with shiled, lots of ways to bypass it

Leblanc counters veigar HARD
harder then Kassadin

But anivia and Kasadin are both counters to him too

Kassadin is countered by Pantheon too.

Wtf is Gangplank and Urgot doing in the list? Just make it all ap or you'll have to list all champs... Not a very good list generally, atleast everything I play is totally wrong there and I won't be bothered to explain why because it would require writing a huge wall of text. Sorry.

Brand counters way more champs than just one xD
For example how can u put Veigar as a counter to Annie before Brand

AD sion counters vladimir 1v1

You dare to post **** like this? In one second I can point more counters and mark your mistakes.
1. Swain is counter for Sion, Morgana, Vladimir, Kassadin, Akali.
Akali has no real chance vs him, unless she is top lane and can camp in the bush.
Kassadin has hard time with him early on - Swains E has same range as Kass Q. He silence you, but before that you E+Q+ autoattack or two autoattacks. Guess who takes much more damage. Swain has his passive for mana regen so he can continue harass, while Kassadin can't.
Vladimir - you can outharass him easily early on, after lvl 6 Swain has great sustain and hid E+ignite wrecks Vlad in his trollpool.
Sion - you can destroy his shield easily and deal more damage if you autoattack. Sion runs out of mana much faster, has no farm, can't gank.
Morgana - lvl 1 black shield is not enough vs Swain. You use EQ, land W after shield is gone and harass her with autoattacks. After lvl 6 You can easily outharass her and survive her combo.

2. Katarina is counterpick for almost every champion based on skillshoots. You can eat every Kennen, Morgana, Brand, Anivia (it's hard after 6 though), Cassiopeia (dodging everything, harassing from great range, dodging her ultimate with Shunpo for easy lotus), Karthus (please, just rapefest), good Kata will deal with Akali too.

3. Fiddlestick is countered by EVERY champion that has long range heavy cc. Every. So don't even post him as mid champion. Ahri? You must have been thinking very hard about it

4. Swain is countered by almost every champion based on mobility and with decent range. Kennen for example, Kat too, of course.

5. Veigar counters Karthus SO DAMM HARD that I have no words for your "list".
He also takes on Kennen with ease, if you can stun properly. Later with DFG you can 1-shoot Kennen when he flashes in your team with his ultimate. Thats great counter.

6. Xerath is countered by mobility champions. Katarina, Kennen, Vlad with his trollpool.

Just that crossed my mind after first look at your "list".

Work on it or gtfo with that trash

Remove Anivia from Xerath counters and replace it with Ahri..