Border War is a set of fantasy skirmish rules.
Spartan Games now offers its Uncharted Seas rules for free.
From Spartan Games:
For the first time, Spartan Games has made the Uncharted Seas Rulebook FREE for anyone to download from our website. Set in an exciting and deadly fantasy realm, the Uncharted Seas is a fast paced naval game that delivers plenty of fun as you game with our stunningly detailed miniatures.
In this fantastical realm you will recreate in miniature the exploits of various races, including the Dragon Lords, Iron Dwarves, Imperial Humans, Shroud Mages, Bone Griffons, Orc Raiders, Thaniras Elves, Ralgard and the Sky Pirates. Everything you need to know in order to be able to play a game is in the rulebook, and we are now pleased to be able to digitally share Uncharted Seas with even more gamers around the world.
Wrath of Kings is a set of demo rules for a fantasy skirmish system. It has some interesting concepts.
Dungeon Delver is a free print and play card game of dungeon exploration.
Fields of War is a set of free wargames rules for fantasy armies. In addition to the core rules, there also are a large number of interesting army lists.