Men & Supermen
A game distributed under the GNU Free Documentation License.
Panels
Tabletop game which paints the world of superheroes in broad strokes. Numerically light, almost free form rules.
Powergame Home Page
Powergame is a free superhero RPG which has been in development since 1994. It is designed to cater for all levels of superheroic campaigns within a simple rules framework. There are currently two supplements available, and a new edition will be released in early 1999.
Risus Supers Version 1.1
Provides simple game mechanics to simulate superheroes who no one takes seriously. Includes character cliches and rules for common contests.
Rumble
A simple and fast paced system with a large list of super powers.
Super Heroes and Heroines
Designed to portray superheroes who have personal lives.
Super Human High School
Game where players take the roles of ordinary teenagers who posses mutant powers.