JAGS stands for Just Another Game System and is described as a “rules heavy” universal RPG system. It’s gotten some notice around the ‘net and is available for free as a pdf or you can pay to get a print version.
Role Playing Games
The Basic Fantasy Role Playing Game
The Basic Fantasy Role Playing game is just that — a role playing game released under the Open Game License. it’s based on the d20 3.5 rules, but takes its inspiration from old school role playing.
Buffy The Vampire Slayer RPG
A lite version of The Buffy The Vampire Slayer RPG rules are available at the BBC, of all places.
Ironsworn Free RPG
Ironsworn is a fantasy RPG that can be played with a traditional GM, as a co-op, or solo game. In this setting, players are heros pursing quests. There is a free downloadable version, as well as commercial soft and hard cover editions.
Pocket Dungeon Game
Pocket Dungeon is a small, solo dungeon game that uses the pocketmod small booklet printing system.