The impetus for this particular playlist was a collection of songs I could play before my monster-themed freshman composition class. But then I just turned it into a more generic spooky themed playlist when I was done teaching that class.
I'm gonna go off-topic, because I love this...my book club for my 4th graders is on a book about a Mexican-American girl who is obsessed with punk music, so I play kid-friendly songs by The Ramones, Green Day, etc. Kids are actually getting a kick out of it. They're lovely at this age.
Honestly, my dad and I throw on a/the Spotify Halloween playlist during trick or treating, and I (uncostumed) pass out the candy, while he (costumed as an Uncle Fester-like hunchback who groans and stuff) scares the living hell out of all the neighborhood children. All I can remember is the Monster Mash is a very important part of this list.
Black Sabbath seems very Halloween.