There MUST be 31 films:
6 countries (USA, Spain, China, UK, Germany, Japan)
8 decades (1920s, 1940s, 1960s, 1970s, 1980s, 1990s, 2000s, 2010s)
2 post apocalyptic or natural disaster related films (Dawn of the Dead, Escape From New York)
1 film with Robert Englund (The Phantom of the Opera)
1 something is underground film (As Above So Below)
3 Satan/Devil centered films (Devil Curse, Rosemary's Baby, The Legacy)
1 Amicus film. (The House That Dripped Blood)
The worst Dracula film (by Letterboxd rating) that you haven't seen and can access. (Dracula 3000)
1 LGBTQ+ connected film (A Nightmare on Elm Street 2)
5 Films from De Palma, Wes Craven, Ken Russell, Hitchcock and/or Moorehead & Benson. (Dressed To Kill, The Hills Have Eyes, The Lair of the White Worm, Rope, Altered States)
2 Peter Cushing films (Horror Express, The House That Dripped Blood)
1 film based on a work of or invoking the name Bram Stoker (Nosferatu)
1 film based on a Clive Barker story (Candyman)
1 film that was released the year that you turned 10 (Coldfish)
1 Mario Bava film. (Blood and Black Lace)
1 film with an 'x' in the title (Edge of the Axe)

And 1 Tobe Hooper Film (There must ALWAYS be a Hooper film) (Lifeforce)

The rest:
Limbo
Boardinghouse
Suicide Club
Ginger Snaps
Prom Night
Massacre at Central High
Suspiria
Mr. Vampire II
Pearl