QUICK EASY RULES:

There must be 31 films

6 countries:
Korea (The Wailing)
Japan (Ringu, Vampire Hunter D,...)
Germany (The German Chainsaw Massacre)
USA (X, Event Horizion, ...)
Italy (Suspiria)
France (Martyrs, Eyes without a Face)
and more

8 decades
2020s (X)
2010s (The Void, ...)
2000s (Vampire Hunter D: Bloodlust, Martyrs)
1990s (Candyman, ...)
1980s (Videodrome)
1970s (Suspiria, Phase IV, ...)
1960s (Eyes without a Face)
1950s (Dracula)
1920s (The Cabinet of Dr. Caligari)

2 insect centered films
Phase IV
The Fly

1 horror film set in space or the future (relative to when it was released)
Event Horizon

2 animated films
Vampire Hunter D
Vampire Hunter D: Bloodlust

1 bloodthirsty old person/people film
Manhunter

2 1970s regional US films (Thanks Sean Young)
Multiple Maniacs
Scalpel

The worst horror sequel from the 1990s that you haven't seen and can access. (I realize that this will take a little work)
From Dusk Till Dawn 2: Texas Blood Money

1 German Silent
The Cabinet of Dr. Caligari

5 Films from David Cronenberg, Ti West, Bill Rebane, Charles B. Pierce, William Grefe and/or Joy N. Houck Jr.
Videodrome (Cronenberg)
The Brood (Cronenberg)
Dead Ringers (Cronenberg)
X (Ti West)
Blood Harvest (Rebane)

2 Christopher Lee films
The Wicker Man
Dracula

1 film with a musician or band in it (A real life musician or band)
Videodrome (Blondie)

1 Stephen King adaptation that is not the first go around.
IT (2017)

1 Lon Chaney film. (NOT JR)
The Phantom of the Opera

And 1 Tobe Hooper Film (There must ALWAYS be a Hooper film)
The Texas Chainsaw Massacre

***FOR THOSE THAT LIKE TO DO EXTRA WORK: WATCH The Last Circus and Silent Madness. Like last year, there is a third film: Pennywise: The Story of It.