I don't get to dig them out as much as I'd like, but my D&D sourcebooks and monster manuals are one of my gaming cupboard's greatest treasures, and now I'm very keen to add this unofficial Darkest Dungeon monster manual to my collection, because it looks awesome.
Dungeon Master Tuz creates homebrew content and monsters for D&D 5th Edition—check out their Patreon—and this week showed off their work-in-progress monster manual, which can be found in PDF form here.
It's the spitting image of a proper D&D book, but with elves and bugbears swapped for Darkest Dungeon's swinefolk, brigands and other assorted nasties. Along with art from the game, each entry has a nice chunk of lore, D&D-style stat boxes and the occasional special rules.
Tuz has been working on the manual for nearly a year and might continue the series if people are interested. It's been designed for low-level characters, so if you fancy starting fresh in a new game and don't mind being assaulted by eldritch nightmares, you might want to bring this out next game night.