The first ever SNK Vs. Capcom game came in the form of Card Fighters' Clash, a title which was an exclusive to SNK's Neo Geo Pocket Color console. The game involves your character walking around lots of different areas to collect cards and fight other card players. With over 300 cards, collecting them all takes a long time. There are two versions of the game -one for SNK, one for Capcom, and to get every card you'll need both.
These games remained relatively obscure, as the Neo Geo Pocket Color wasn't a very popular console. Things would be amended in 2022, when the games were released for the Nintendo Switch.