Krendel is a free, universal RPG. It is really an impressive work, well written, with numerous illustrations. The mechanics are also worth a look. I can see the single roll mechanics being adapted to skirmish rules for miniatures as well as for use in RPGs.
Role Playing Games
Legends of Time and Space
Legends of Time and Space is a free role playing game that takes its inspiration from Steve Jackson Games’ The Fantasy Trip.
The Fantasy Trip Compendium of Resources
Metagaming’s The Fantasy Trip is one of my favorite games of all time. It’s one of the core products that drew me inexorably into the gaming world. Here’s a page with a great number of resources for The Fantasy Trip.
Microlite 74 RPG Tablet Friendly Edition
Microlite 74 is a set of free role playing rules that emulates the original edition of a certain world famous role playing game.
Microlite 81 Complete
Microlite 81 is an old school RPG with the flavor of a certain game released circa 1981. The author writes:
The first (and with luck only) Release Candidate version of Microlite81 Complete is now available for download and comment. Microlite81 Complete is intended to be standard Microlite81 with more complete descriptions of spells, monsters, and magic items and a few extras like an example of play and instructions for GMs which will hopefully make the game more friendly to players with less experience with old school gaming. Microlite81 Complete allows the GM to select which version of the “core game rules” to use (the standard B/X-like rules from Microlite81 or the B/X-like rules with the author’s house rules from the early 1980s added as in Microlite81 Extended).