Here's some horror movies that take place on or around halloween that I really like:

-Trick 'r Treat

-The entire Halloween series (I think either the first or the third are the most "halloween" to me. The third one is completely unrelated to anything so you don't need to have watched to others)

-Terrifier 1 and 2 (Don't watch if you don't like gore. Actually don't watch unless you really like gore, because these movies don't have much else.)

-Ghostwatch