UFS, seconded. Through some dark magic, that CCG line covered:
-King of Fighters
-the webcomic Penny Arcade
And... it was a fun card game, to boot. A bit more mechanically complex than Magic, but once you got comfortable with it, the game really felt like a 1-on-1 fight. You could perform combos & other standard fighting game tactics, characters' mechanics led them to function like you'd expect (Nightmare & Siegfried were slow, but packed a wallop), and there was an element of reading your opponent (the decks didn't play themselves). When (presumably) the licencing ran out, the creators even kept the game alive for a while with original characters.
There was also another competing fighting CCG, Epic Battles, that covered Street Fighter, Mortal Kombat, and Tekken. That one was a bit easier to learn, but it came & went with little fanfare. On Oahu in 2006, the only place I could find that stocked EB was Blockbuster Video! I eventually knew where every Blockbuster was on the whole island.