Reddit reviews S. Petersen's Field Guide to Creatures of the Dreamlands (Call of Cthulhu Horror Roleplaying)

While I don't like the Dreamland stories, they do have a lot of neat Lovecraftian monsters that often get forgotten.

Gugs, giant vertical mouthed hairy monsters with two sets of forarms and feet like T-Rex.

Zoogs, little tentacle-faced opossum critters that eat wayward dreamers.

The Cats of Ulthar, kitties that can teleport through space-time and also eat you if you are mean to them.

Men of Leng, saytr type creatures that sail around on flying galleons.

If you haven't already, I'd recommend buying Peterson's Guide to the Dreamlands It's all done in colored pencil too, and looks incredible.