Nightmares 1 is a collection of monsters for 5e by Cthulhu-famous Petersen Games. It gets a thumb up from this reviewer.
Dark Worlds: The Ritual D&D adventure review
A review of Dark Worlds: The Ritual. This set of adventures brings the cosmic horror of the Cthulhu mythos to fantasy heroes.
The Devil’s City brings America’s first serial killer to 5th edition
The Devil’s City: Horror Fiction & 5e Gaming Conjoined is a project to fund the full-length RPG campaign sourcebook Horror in the Windy City which expands on Whispers in the Dark.
Milestone horror: A review of the Whispers in the Dark quickstart
The emphasis of this book is helping you use 5e rules to create those Lovecraftian stories and testing the modified system with the adventure. It’s about the atmosphere.