2006 saw the release of Card Fighters DS in Japan, exclusively for the Nintendo DS. American and European versions were released in 2007. I haven't played this much but the game is similar to the Neo Geo Pocket versions, but now there are even more cards. The likes of Dante from Devil May Cry and some World Heroes characters now have their own cards. Most of the Final Fight cards from the previous game are back, along with a few extra additions.
Shortly after the game was released, a bug was discovered that made the game freeze. If you beat the game and then play through it for a second time, you will eventually have to fight an opponent called Jon, who is on the 9th floor. The game will crash when you talk to him. SNK had a product recall and fixed any game cards they received, but they apparently have stopped offering this service now. The game had a mixed reception, and several reviews I've read have called it an inferior game to the NGPC titles.