Aquanautica Imperialis is a set of free wargames rules for naval battles in the Warhammer 40K universe. The underwater rules are found here.
Warhammer 40K variant
In The Emperor’s Name v. 3.0
In The Emperor’s Name is a set of free wargames rules for skirmish games in the Warhammer 40K Universe. Theyr’e not up to version 3.0.
Aquanautica Imperialis Warhammer 40K Naval Rules
Aquanautica Imperialis is a set of rules for naval games in the world of Warhammer 40K.
Warhammer 40K Darkest Africa Variant
Even if you don’t like the science fiction game, Warhammer turns out to be a pretty flexible system for playing other periods. Plus, it has the advantage of familiar mechanics and a built-in player base. So given that, its not surprising that it’s been extended to practically every period you can think of. Here’s a variant of Warhmamer 40K for colonial games in darkest Africa.
Rabbidgerbal’s Super Simple 1PG Sci-fi Skermish Rules
Rabbidgerbal’s Super Simple 1PG Sci-fi Skermish Rules is a set of free wargames rules meant as a 40K replacement.
Yes, that’s really how the author spelled “Skirmish”