One Page Kill Team is a set of free science fiction rules for small skirmishes. The authors write:
One Page Kill Team is a single-page ruleset designed to be fast to learn and simple to play. It is a great way to play with just a handful of miniatures and experience heroic skirmishes in a short time.
– Updated January 2015
Land of the Lead has a set of one-page Napoleonics Rules. They’re designed for play with a “reinforced division” per side. Scroll down to the bottom of the page to find them.
From the author:
Blaster is a generic SciFi RPG in the 26th century where mankind’s unity has been sundered by war and where a few good men can still make a difference.
More like Firefly and Buck Rogers (the 1930′s version) than Star Trek you will form a team of adventurers who have a small starship which they can use to explore, travel, trade and fight against the dying of the light.
As usual both the core rules and the setting are single page affairs and are completely compatible with other titles in the Dead Simple RPG series.
Fubar is a good looking one page set of modern and science fiction rules.
The folk at One Page Rules have released version 2.3 of their Age of Fantasy Generic Rules. The rules have one page (front and back), and there is a vast list of army and faction stats to download as well.