One of the best is 'The Call of Cthulhu' by H.P. Lovecraft. It introduces the terrifying Cthulhu, an ancient and powerful being. Another great one is 'At the Mountains of Madness', which takes readers on a chilling journey in Antarctica, filled with strange and otherworldly creatures. And 'The Colour Out of Space' is also a classic, with its tale of a strange color that brings destruction and madness to a rural area.
Some of the best eldritch horror stories include 'The Rats in the Walls' by Lovecraft. It has a great build - up of horror as the protagonist discovers the secrets hidden within the walls. Also, 'The Case of Charles Dexter Ward' is notable. It explores themes of resurrection and the blurring of boundaries between life and death. 'The Whisperer in Darkness' is another good one, with its mind - bending plot and the introduction of the Mi - Go, a race of alien entities.