Console games don’t have that long of a history to begin with, but even among them, one game is never mentioned. In 2003, Sega released a sequel to its popular Phantasy Star Online series for the Gamecube. It was called PSO Episode 3: Card Revolution, and it was a radical departure from the series, and another console first: the first online card battling game.
The gameplay was unique. There were two sides to the conflict: The Hero side, and the Arkz side. The Hero side used cards to equip weapons and defensive items and defeat the Arkz command character. The Arkz used cards containing classic PSO monsters and tried to defeat the Hero character, by destroying his damage and reducing his HP to 0. They both moved and set items based on random dice rolls, on a grid of varying size and configuration. It’s a suprisingly deep system, and a lot of fun to play. A story mode was includes, as well as online head-to-head action. However it wasn’t what most people expected.
Unfortunately I never got to play the online version. It came out when I was in the middle of a move, and had sworn off MMOs to get used to my new location. It’s defunct now, the servers offlining in 2007. You may be able to find it quite cheaply used, and it is fun even in its offline mode. It’s filled with nice little touches, like your friends list from PSO transferring over, and free cards given based on what saves form other Sega games are on your memory card. If you haven’t, I recommend picking it up and keeping it as a piece of online console history.