Living Dead is a set of free roleplaying rules for the zombie apocalypse.
Dragon Slayers is a playest version of an upcoming free role playing game. The author writes:
Dragon Slayers RPG looks like Savage Worlds but plays like D&D 5e. The goal is to have D&D-style adventuring without the fiddly bits. GMing is easy and the game is great for new players and one-shots. It features step-die mechanics and has inherited a few dirty hippie quirks (abstract equipment, 13th Age style backgrounds). Magic is low-ish powered and mages cast with spell points.
Contagion is a role playing game of modern horror, in which the forces of Heaven and Hell are fighting for the souls of mankind.
Force 9 is science fiction role playing game inspired by Alien and Starship Troopers.
I remember Ysgarth from my role playing days in the late 1970s. The game first was published in 1979. It was one of a number of fantasy rpgs that I remember we tried before finally settling on the Warhammer Fantasy Role Play.
Ysgarth has got a pretty complex system of skills and attributes, but action is resolved on a simple d100 (that is, you roll 2d10s and read them as separate decimals)