I enjoy single-author story collections. So, in roughly chronological order by publication of the earliest story contained (rather than of the collection as a whole), here is a single-author story collection for each day of October (plus 2, if you're a fast reader).
Nothing here by Poe, Lovecraft or Stephen King, because even casual readers may know those authors. And I'm still working on finishing a few of these titles (like the Benson, Etchison, Campbell and Ashton Smith) but I've read significant portions of them and feel comfortable suggesting them. Not every story will be out-and-out horrific -- for instance, the John Collier collection also contains crime/mystery and fantasy; the Clark Ashton Smith contains some poetry -- but the things that go bump in the night in these stories all have greatly repaid in entertainment my reading, and often rereading.