PySolFC can support adding additional games, or making other modifications by writing Python scripts that work as plugins. These scripts can be added to the plugins folder of your user folder or the PySolFC installation directory. Plugins can be used to create and add games that are too complex for the Solitaire Wizard options.
A couple sample plugins are available for download on the PySolFC website here. These plugins recreate a couple of PySol's more complex games, including Demons and Thieves and Crossword and can be used as a guide to help write your own plugins.