Were there any card games like Magic: The Gathering for retro systems? I expect not, because the digital card game genre didn't really "click" until later. But I thought I'd ask.
The Neo Geo Pocket Color has a fantastic card battler called SNK vs. Capcom Card Fighters Clash that comes in SNK and Capcom varieties. Great game on a great system. Pairs well with the unbelievably good fighting game on the same system.
Pokemon TCG 1+2 are all that come to mind, for me. If you want to stretch the definition a bit, the Megaman Battle Network series for the GBA has a deckbuilding aspect to it, but it's more of an action RPG.