Sally Forth Miniatures offers a free set of rules for playing solo Science Fiction miniatures games. While designed for ACP164, they are adaptable to any sci-fi miniatures system, such as WH40K, Void, Star Wars, etc.
Miniatures Rules
Space Rat RPG
Space Rat is an RPG written by Nathan Russell in just 24 hours. It’s inspired by the cheesy science fiction movies of the 70s. It looks like a lot of fun.
Big Game Hunt Dinosaur Hunting Rules
Big Game Hunt is a game of dinosaur hunting. Really.
Fallout Warfare
Fallout Warfare is a set of miniatures rules for playing games set in the universe of the acclaimed Fallout computer game.
WarZone Photo Gallery and House Rules
Redjack has an attractive photo gallery of figures from the late, but great Warzone game. I’ve got a ton of those figures myself.
There also are a couple of Warzone scenarios and house rules