By threedeesixWhile I have nothing against the Sanity rules of Call of Cthulhu, I don't think they are necessarily suitable for all horror settings when simulating Fear. Another horror RPG that I believe does it just as well, if not better for my uses, is Pacesetter's Chill.
Years ago, I translated the Fear Check rules to BRP for a yearly Halloween BRP Chill game that I ran for more then a decade. Here are those rules, along with the rules for Sensing the Unknown. These rules are written by Michael Williams and only converted by myself.
Chill Fear and Sensing the Unknown.pdf
By threedeesixYears ago, I ran a yearly Halloween BRP Chill game for more then a decade. Here is one of the adventures that I converted to BRP during the playtest. The adventure is only converted by myself, and I do not claim ownership of the material.
By SDLearyDelta Green: Need to Know is their quick-start rules that they have decided to make available to everyone!