Two very useful reading lists here.
The first, Women of Horror, Dark Fantasy, and the Weird: A Recommended Reading List, lists tales, novels, and even poetry from those genres and looks intriguingly non-mainstream.
Then, a list of Horror in Translation from Rachel Cordasco, which again promises some unusual reading in translation from German, Dutch, Japanese, Spanish, Italian, and Swedish. Rachel Cordasco also has a website which specialises in Speculative Fiction in translation (I’ve added this link to the Related Links column on the right-hand side).