For those who like to get in on the ground floor, Wildfire Games has an open Beta Test of its new CthulhuTech RPG Core Book.
RPG Horror
Living Dead Zombie Rules
Living Dead is a set of free roleplaying rules for the zombie apocalypse.
Contagion Role Playing Game
Contagion is a role playing game of modern horror, in which the forces of Heaven and Hell are fighting for the souls of mankind.
Searchers of the Unknown Minimalist RPG Rules
Searchers of the Unknown is a set of free role playing rules. These are one-page, minimalist rules, each of which is designed as a stand-alone product. The collection includes: Searchers of the Unkown, Dwarven Glory (and supplement), Karry on Krawling, Witches of N’kai, Adventurers!, Cyborg Samurai Are Go!, Dirty Rotten Scoundrels, Funkin Fists of Fu, Jung Guns, Raiders of the Unknown, The Bastards, Brickmasters of the Unknown, Mutant Got Gunz, Mutant Scavengers of the Ruined Earth (and supplement), Tempora Mutantur (and supplements), Searchers in Spaaaace!!!, Scavengers & Spacewrecks, Swashbucklers of Mars (and a supplement), and Song of the Symbi.
44: A Game of Automatic Fear – Free RPG
44: A Game of Automatic Fear is a free rpg set in a 1950s where a conspiracy is replacing humanity with robots.