Great Old Ones offer the rules for a two player card game where the goal is to reduce your opponent’s sanity to “0.” You need to make your own cards to play.
Druid’s Duel is a strategy card game — played with a poker deck — for two to four players. It simulates a duel between shape-shifting magicians.
WarpSpawn offers Commodore, a two player card game of Napoleonic fighting sail.
Richelieu is a card game based on the efforts of Mary of Medici to have the young Louis the XIIIth dismiss the Cardinal of Richelieu.
Board Game geek has downloads of the rules and all the files needed to play.
The Great Game is a set of rules for a two player card game in which the Russians and British vie for dominance in Central Asia.