Sword and Planet Resources

Rule Systems

Warriors of the Red Planet (POD) (Blog)

Grim Tales (HC) (Forum)

• Adventure: Slavelords of Cydonia

Under the Moons of Zoon (Website) (free PDF) (POD)

MARS (d20 PDF) (Savage Worlds PDF) (Savage Worlds HC)

• Amazing MARS PDF bundle, including main rulebook plus seven adventures, a sandbox, and a miniatures combat supplement to Showdown. All for $9.99.

Adventures/Sandboxes

OSR
Peril on the Purple Planet

• An upcoming DCC boxed adventure and setting set.

Carcosa (PDF)

• A science fantasy sandbox setting for Lamentations of the Flame Princess.

Apocalypse World
Adventures on Dungeon Planet (PDF/POD)

• This is a science fantasy supplement.

Fanzines

DCC
Crawljammer -- this fanzine has resources for running DCC as a Spelljammer-style science fantasy campaign.