Silent Dark (direct download link) is a set of free wargames rules for “tactical” science fiction games.
Rules: Science Fiction
Titan Rampant – SciFi Dragon Rampant Variant
Titan Rampant is a free variant for the commercial Dragon Rampant rules. Ownership or access to Dragon Rampant is required for play.
Free Project Z Rules From Warlord
Warlord Games is offering a free pdf of their Project Z zombie miniatures rules.
Beyond The Gates of Antares Quick Start Rules
Warlord Games offers a set of free quick start rules for their science fiction small unit game, Beyond the Gates of Antares.
Death Squads 41st Millennium Rules
Death Squads is a set of rules for small scale skirmish conflicts in the 41st Millennium.