RPG Now has a free horror RPG module called Dead of Night: Night of the Santa Claws. It’s designed for the Dead of Night RPG, but no doubt could be modded for any other system.
RPG Horror
Scooby Doo Cthulhu
Here are some stats for using the Scooby Doo characters with Chaosiums’ Call of Cthulhu game.
Scooby v Cthulhu. I wonder which one is going to have to make the sanity check?
Fickle RPG
Fickle RPG is
a narrative roleplaying and cooperative storytelling game, distinguished by the core dice resolution mechanic which has bluffing, bidding, and meaningful decisions. The game is a universal system that can be played in any genre, such as sci-fi, military, zombies, high fantasy, superheroes, etc. An ongoing campaign can be played over multiple game sessions, or as a themed one-shot.
Dread Roleplaying Game
Dread is a role playing game that uses an innovative mechanic — a Jenga game — to resolve actions and build tension.
There are both free and paid versions.
CthulhuTech RPG Rules
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.