For the recently released Frostgrave rules, here are a set of print-and-play spell cards.
fantasy
Warthrone Fantasy Battles Rules
Warthrone is a set of free wargames rules for fighting fantasy battles. You may find it an acceptable (or superior) replacement for Warhammer Fantasy Battles.
Age of Sigmar Free Rules and Warscrolls
In a pretty interesting turn of events, Games Workshop now offers the rules and army lists for its fantasy miniatures game for free.
I actually see this as the final death throes of the game.
Kensei Samurai Rules
Kensi is a set of free wargames rules for samurai warfare ranging from skirmishes to large battles. The rules include a fantasy element, and the world is a not-quite-historical Japan.
Wrath of the Gods Fantasy Skirmish Game
Wrath of the Gods is a set of free wargames rules for skirmishes with a classical mythological flavor.