All of the new categories have been revealed! From here on out, you get recycled categories from years past. On the bright side, we've already got a whole bunch of suggestions for them with Murder By Death's brilliant Halloween Bingo lists from the last two years
Classic horror: horror fiction that was published prior to 1980;
Book suggestions: check out this list: MBD's list for Classic Horror. In addition, as someone who is not a horror fan, classic horror is one of my favorite squares! I definitely recommend The Haunting of Hill House by Shirley Jackson, Uncle Silas by Sheridan LeFanu and Dracula by Bram Stoker, which is best as a full-cast audiobook.
Romantic suspense: any romance which has a significant sub-plot that involves mystery, thriller or suspense.
Book suggestions: MBD's list for Romantic Suspense. Also, this is pretty much your only chance to get any romance into your bingo, so I recommend checking out almost anything by Mary Stewart, but especially The Moonspinners, Window on the Square by Phyllis Whitney, or Mistress of Mellyn by Victoria Holt.
Gothic: any book with significant: a genre or mode of literature and film that combines fiction and horror, death, and at times romance.
Book suggestions: Pretty much anything by Daphne du Maurier would be considered gothic, including Jamaica Inn, Jane Steele by Lyndsay Faye is a really fun retelling of Jane Eyre, with Jane as a killer and carrying the tag line "Reader, I Murdered Him," and another retelling of Henry James The Turn of the Screw, Florence and Giles, by John Harding, which I have not read, but which looks interesting. For more suggestions, check out MBD's list for Gothic.
Country house mystery: a closed circle murder set during a gathering like a house party.
Book suggestions: These are some of my favorite mysteries, and there is some overlap with the next category, Terror in a Small Town. You can find a bunch of options on MBD's list for Country House Mystery, and one of my personal favorites off of that list is And Then There Were None by Agatha Christie. In addition, Hunter's Green by Phyllis Whitney would fit, if you're interested in something more gothic and less mystery
Terror in a small town: any mystery, supernatural, horror or suspense that takes place in a small town.
Book suggestions: A few suggestions for this square include: Hex by Thomas Olde Heuteveld, We Have Always Lived in the Castle by Shirley Jackson, and one of the best of all of the Agatha Christies, The Murder of Roger Ackroyd, which is already included on MBD's list for Terror in a Small Town.