MCU fanfic. Captain America becomes an eldritch hero.

A store chock-full of C'thuliana, from stickers to shirts to books. Fun to poke around in.

A short story written by Neil Gaiman as a dictated autobiography of C'thul'hu.

The C'thulhu Mythos in the modern day (kinda). UFOs, the paranormal, and a horse doctor's dose of government black ops.

A web application that lets you randomly generate the contents of a greenbox (a hidden stash of equipment) for the tabletop RPG Delta Green. The Generator will also let you add your own items to the database.

A lorem ipsum generator that churns out Lovecraftian creature babbling and wailing. If you want to create a mythos tome, an evocation, or just random looking text to fill out some fields this will work.

A wiki about the Sherlock Holmes canon and mythos.

A blog dedicated to C'thul'hu mythos-related props and other crafts.

A wiki dedicated to the aspects of the Yellow Sign.

The homepage of a Lovecraftian hip-hop group. Pretty good stuff - I recommend McMurdo Boogie, after At the Mountains of Madness.