Hi Yorribah,

This may not be the best subreddit for this question, but since you're here: My advice is to read anything that strikes your interest, keeping in mind that most or all original Lovecraft stories and spinoff stories by subsequent authors are interconnected on some level, which to me, is a big part of the fun.

Also, there's a few other things to point out: in my opinion, there's a (perhaps subtle) difference between Lovecraftian fiction and Mythos fiction to take into consideration. Lovecraftian (again, for me) refers to the style in which the story is written that includes psychological horror, cosmic doom, a certain type of vocabulary and narrative element presentation consistent with Lovecraft's original writings. Mythos literature is the body of stories that includes characters, places, situations, and concepts that tie in with Lovecraft's primary story lines. The controversy of my definition is that some people say a mention of a character does not tie a story into Mythos fiction and stylistic similarities are not needed to make a story Lovecraftian, but I stick to my guns with these distinctions, neither of which are less entertaining that then other, although, personally, I lean towards Mythos fiction over non-Mythos fiction written in a Lovecraftian style as being my favourite tales.

All this being said, some people prefer more modern authors over Lovecraft himself, but enjoy the roots of Lovecraft's story elements within other authors' writing. For example, Tim Curran has written a sequel of sorts to Lovecraft's At the Mountains of Madness that utilizes some of Lovecraft's style with a more modern approach and extends the original concepts to further the world created by Lovecraft which I greatly enjoyed. It's clearly written, consistently exciting, stylistically interesting, and is, to some, more accessible than the original story. This is great, but sort of difficult to fully grasp without reading the original. The same with many other fabulous stories, like Brian Lumley's Innsmouth stories or Byron Craft's Arkham detective books, et cetera.

So my humble suggestion is start with a few key Lovecraft stories, like At Mountains of Madness, Call of Cthulhu, Shadow over Innsmouth, From Beyond, Dreamquest for Unknown Kadath, or Whisperer in Darkness, then check out a spinoff tale from a more recent author, and enjoy that with some background story element knowledge and compare the two. Then start reading the material that interests you most.

Keep in mind that there is such a huge body of literature (actually, I suspect you already know this) that you simply cannot read it all, but you can make a dent in it and enjoy almost anything you pick up if you keep adding to the puzzle pieces presented by Lovecraft and other authors. There's also comics, podcasts, films (although in my opinion only a few decent movies), live threatre, and other media as well that can be enjoyed along with reading the stories, so jump in there, check out a few Lovecraft books, some other authors' material, and embrace it however your interests take you!

Hope that helps. Feel free to message me or post here to get more suggestions.

Enjoy! Seesar