Good morning, Story Games.
Here is Cthulhu Dark, my rules-light Lovecraftian game
. (It gets its name because it's essentially Cthulhu Light, but you can't call a Cthulhu game that, so it's Dark.)
I've been playing this for a while and it works remarkably well. The rules are fun and incredibly minimal: they fit on one sheet of paper. You don't need a character sheet to play, so you can start playing after two minutes of prep. And, despite the simplicity, there are some interesting rules twists: look at the Suppressing Knowledge rule for an example.
At the moment, it's designed for running prewritten Cthulhu scenarios. In time, I'd like it to work for improvised and perhaps GMless games. There'll be some equivalent of Apocalypse World's Fronts, which lets you advance the horror bit by bit.
Also, here is a really important thing. One of the main reasons for writing Cthulhu Dark was that people wanted to buy my scenarios without buying a rules book. So, I wrote Cthulhu Dark, to let me publish them as standalone products.
You can do the same. I know various people on Story Games write Cthulhu scenarios: if you want to publish them, without being dependent on an external system, you are very, very welcome to use Cthulhu Dark. Put simply, you include Cthulhu Dark at the back of a scenario, free of charge, and publish it as a standalone thing. Here are some more details