Dice For Honor is a set of free wargames rules for Samurai Skirmishes.
pike and shot
Heroic Samurai
Jim Wallman offers Heroic Samurai, a set of free wargames rules for clan warfare in feudal Japan.
Yume no Bushi – Dream of the Warrior
Yume no Bushi – Dream of the Warrior is a set of free wargames rules for samurai skirmishes in the Chanbarra movie tradition. Think westerns, but in a samurai setting.
Gott Mit Uns Thirty Years War Rules
Gott Mit Uns is a set of free wargames rules for the Thirty Years War. The author writes:
Gott Mit Uns (GMU) is a tabletop miniature wargames simulation of the Thirty Years War (1618-1648) that lets players refight the largest battles and seiges in a historic and enjoyable way, from White Mountain to Norlingen and beyond. GMU can be played with two players, one per side, but is more enjoyable and managable as team game, with one player per wing per side (1-4). The best miniature scale for the game is 10mm for visual impact, or 15mm. A 28mm game of GMU would require a very large space.