Não tenho certeza sobre o formato totalmente livre, mas você pode experimentar o PySol
PySol is an exciting collection of more than 200 solitaire card games. Its features include support for lots of distinct games, very nice look and feel, multiple cardsets and table tiles, sound and background music, unlimited undo & redo, load & save games, player statistics and log files, hint system, demo games, support for user written plug-ins, integrated HTML help browser and lots of documentation.
Among the supported games are classics like Aces Up, Baker's Game, Canfield, FreeCell, Forty Thieves, Golf, Klondike, Pyramid, Scorpion, Spider, Yukon, and many more...