The Shining is a print-and-play game based on the Stephen King novel of the same name. King himself apparently participated in playtesting.
Living Dead is a set of free roleplaying rules for the zombie apocalypse.
Comic Book Plus has a collection of free pulp horror comics and stories.
Ravensblight Manor is a free paper model of a haunted house. I took a look at it, and think that it would be just about the right size for 25mm – 28mm figures.
Contagion is a role playing game of modern horror, in which the forces of Heaven and Hell are fighting for the souls of mankind.