Pocket Imperium is a free card game of the Expand, Explore, Exploit and Exterminate genre. It’s designed for three players (not many of these) and uses just 18! cards.
Science Fiction
Bosconian D Solo Board Game
James Catalano offers Bosconian D, a free solo boardgame based on the classic Namco video game. To find it, you have to scroll down to the bottom of the page, past his (very cool) retro video games downloads.
Pulp Science Fiction Inspiration
This Flickr album has a series of covers of British pulp science fiction magazines. There’s lots here for inspiration.