Original Hooptober here

There must be 31 films
6 countries

Germany: Vampyr
Japan: Onibaba
Czechoslovakia: The Cremator
Italy: Suspiria
Spain: [REC]
Iran: A Girl Walks Home Alone at Night

8 decades

20s: The Cabinet of Dr. Caligari
30's: The Invisible Man
50's House of Wax
60's: Night of the Living Dead
70's: Eraserhead
80's: Inferno
90's: Braindead
2020's: Barbarian

2 post apocalyptic or natural disaster related films

Dawn of the Dead
Color Out of Space

1 film with Robert Englund

A Nightmare on Elm Street

1 something is underground film

Dead & Buried

3 Satan/Devil centered films

Rosemary’s Baby
The Omen
The Wailing 

1 Amicus film.

The Skull

The worst Dracula film (by Letterboxd rating) that you haven't seen and can access.

Dracula 3000

1 LGBTQ+ connected film

The Rocky Horror Picture Show

5 Films from De Palma, Wes Craven, Ken Russell, Hitchcock and/or Moorhead & Benson.

Carrie
Scream
Altered States
Psycho
Spring

2 Peter Cushing films

The Curse of Frankenstein
Dracula

1 film based on a work of or invoking the name Bram Stoker

Nosferatu

1 film based on a Clive Barker story

Hellraiser

1 film that was released the year that you turned 10

House of 1000 Corpses

1 Mario Bava film.

Blood and Black Lace

1 film with an 'x' in the title

Häxan

1 Tobe Hooper Film

The Texas Chain Saw Massacre

Extra Work:

The Zodiac Killer
10 Rillington Place

Personal Additions

His House
Creep
Saw X
Friday the 13th franchise (on Friday the 13th)
The Addams Family