Tacship is a set of free wargames rules for space combat by John Tuffley. He writes:
Tacship is a simplified fast-play rules system for simulating combat between manned space fighters. The game may be played on a hex grid map or on a plain table area by substituting inches for hexes and measuring turns in 60 degree increments (the same as a one hexside facing change). Fighter models should be mounted on stands, preferably with a one inch hex base, if a grid is being used.
Full Thrust Cross Dimensions is a Full Thrust rules variant. It brings together rules from the various books and tries out some new ideas.
Hostile Stars is a set of free wargames rules for fighting fleet actions in the Dark Realms universe.
Pacwar is a set of rules for large scale dogfights in “The Universe.”
Generic Outlandishly Big Spacefleets (GOBS) is a set of free and easy-to-play rules for huge fleets of starships. The author writes:
G.O.B.S.! is fast-paced and easy to learn. Record-keeping is minimal; in most cases, ships blow up rather than retaining damage. (A two ship game of G.O.B.S.! would be over pretty quickly. This game is about fleets, Sparky! We want explosions all over the place!) The length of playing time is dependent on the size of your fleets, but an hour or two should do it for most cases. Wanna play longer? Build bigger fleets!