Titan Rampant is a free variant for the commercial Dragon Rampant rules. Ownership or access to Dragon Rampant is required for play.
rules
Free Project Z Rules From Warlord
Warlord Games is offering a free pdf of their Project Z zombie miniatures rules.
Frostgrave House Rules
Here are a set of houserules for Osprey Publishing’s Frostgrave.
Full Command Fantasy Warfare
Full Command Fantasy Warfare is a set of free wargames rules for hex-based fantasy games.
Pocket Tactics 3D Printer Game
Pocket Tactics is a free download and print on your 3D printer game.
I think this is the wave of the future.