I am going to say it’s a neck-and-neck between The Nightmare on Elm St and the Hellraiser series. Both great movies and both getting a 2021 reboot. Awesome!
I loved the Steven King adaptation of Psycho. Bate’s Motel was a real insight into Norman Bates and and his mother, Norma before the events of the famous movie. Great show.
I’ve always been a huge fan of Tales of the Unexpected. In regards to a movie I would have to say The Exorcist. It’s a slow burner but was great for it’s day.
I wouldn’t say it’s classic but the exorcist series was really fun to watch. Great characters and even a few scares. I like how it ties in with the initial movie/book.