BrisKola is a version of the the Italian card game Briscola. It uses an Italian pack of 40 cards (numbers from 1 to 7 and the court, without jokers), or a French pack after taking off the cards from 8 to 10 and the jokers.
Duo is a free implementation of the Crazy Eight or Uno card games. For now, Duo allows you to play against 1, 2, or 3 players controlled by the computer.
This is an attempt at a Euchre game. It's written in C++, interface in GTK+ (glade). There are three levels of AI, with the harder two being good enough to give you a pretty good challenge.
(commercial) Galacticards is a card-based space strategy game.
Generic Collectible Card Game
Generic Collectible Card Game is a multiplayer multiplatform implementation of a card game engine. The card game engine is designed to be of general purpose core for several modules each defining the game specific behaviour.
Gnono is a rewrite for GNOME, under the GPL license, of the Windows card game WUNO. It has French and German language support.
gnupitch is a game based on the card game 'pitch'.
Hearts is a KDE clone of the Windows program, but with additions like support for session management and extra configurable options.
KardsGT includes a suite of card games that feature network play, solo play, and even a career mode. The computer players will each have their own personalities. The currently available games are Cribbage and War.
Lieutnant sKat is a two player cardgame for Linux/KDE2 according to the rules of the German Offiziersskat. Each player has a set of 16 cards and tries to win more points than his/her opponent. This is done by playing a card, trying to win it and then being able to uncover one of your covered cards.
mille is a Mille Bournes game for terminals.
Mindless Automaton is a virtual tabletop on which you can play card games against other people over a network. It was designed to simulate the Magic the Gathering game, but it can be expanded to simulate other games
NetMauMau is a server for the popular card game Mau Mau.
NetSpades is a 4-player client/server game program that allows you to play spades with 3 of your friends across a network.
OpenPref is an open source implementation of European trick-taking game Preferans (or Preference). Some information about game's rules and strategy can be easily found in Wikipedia.
QTruco is an implementation of games played with Spanish cards. It currently supports "Truco" and "Casita Robada" games, player vs. computer AI, and player vs. remote player modes, with multiple AIs available for each game. It includes game rules in English and Spanish.
SDLHana is a SDL-based Hanafuda game, a Japanese-oriented card game.
TkHearts is an clone of the Hearts card game. It's a mostly complete game, but the AI is still being improved.
XMille is the classic game of Mille Bourne for X Windows. It is card game against the computer in which each player tries to reach 700 or 1000 miles in a hand. Each player tries to avoid accidents, flat tires, running out of gas, and break downs while trying to cause these same maladies in the opponent. The final object of the game is to be the first team to accumulate a total of 5,000 points in several hands of play.
xtruco is a traditional Brazilian card game.