A real-time card game is a card game in which there are no turns and all players may act simultaneously (that is, in real-time).
The card game Set has a real-time element; in Set, the players are racing to identify patterns in the cards on the table.
In this family are Spit, Egyptian Ratscrew, and Nerts.
In this family are the 52-card game Pig and Parker Brothers' Chicago Commodities Exchange-themed Pit.
One can also view games like Solitaire and Uno (specifically on the last turn, as real-time per se).