I don’t really get in the groove for holidays, but I tried to do some horror-themed wallpapers, anyway. I’ve added some stuff themed after:
Edgar Allan Poe, H.P. Lovecraft and most scary of all (to me, anyway) William Strunk (of Strunk and White’s Elements of Style).
There is also a wallpaper themed after Dr. Seuss, because you know, he was pretty damned cool. Not very scary, but quite bizarre.