Engle Matrix Games
Engle Matrix Games are a type of game designed by Chris Engle and published by Hamster Games. The games are all the same on a mechanical level, with each game distinguished only by its individual story or setting.
Every Engle Matrix game can be played as a standalone game; there is no core game that it is necessary to purchase.
These games are generally storytelling board games, using discussion between players as a conflict resolution tool, modeled after a real-life psychotherapy tool. Although these games are sometimes referred to as "role-playing games," they seem to be using the psychiatric definition of role-playing rather than the tabletop gaming industry definition.
Unlike most other Cthulhu Mythos-themed games, which treat insanity as an amusing lark, Engle Matrix Games takes an approach closer to real-world psychological therapy.
More information on Engle Matrix Games can be found here: Free Matrix Game Rules.
This is a list of Cthulhu Mythos-themed Engle Matrix Games: