With a little help from Gemini, I’ve put together a curated collection of Cthulhu Mythos stories. This includes some core H.P. Lovecraft canon, most of which I’ve read before, and stories by Robert E. Howard and Ashton Clark Smith, which I have not read. The three authors were in regular contact as they collaborated on these mostly in the 1930s.
DISCLAIMER: All these links seem safe to me, but use your best judgment. Also, I know there are things in Lovecraft’s writing that can be offensive to modern sensibilities, and as I have not read the other stories I don’t know how inoffensive or offensive they might be. Read them with your 1930s hat on and if you feel they are particularly bad, feel free to let me know.

- “The Nameless City” (Lovecraft)
- “The Shadow Kingdom” (Howard)
- “The Call of Cthulhu” (Lovecraft)
- “The Fire of Ashurbanipal” (Howard)
- “The Whisperer in Darkness” (Lovecraft)
- “The Door to Saturn” (Smith)
- “The Coming of the White Worm” (Smith)
- “The Tale of Satampra Zeiros” (Smith)
- “The Shadow Over Innsmouth” (Lovecraft)
- “Worms of the Earth” (Howard)
- “The Mound” (Lovecraft & Bishop)
- “At the Mountains of Madness” (Lovecraft)
- “The Empire of the Necromancers” (Smith)
- “The Colossus of Ylourgne” (Smith)
- “The Dark Eidolon” (Smith)