This book tells you what kind of action films have rarely or never been made and warns you about saturated niches. Authors and screenwriters might want to avoid those. The lower the frequency meter, the more unique the concept.
These statistics are based on about 3000 horror and horror-adjacent movies I've reviewed and rated. 8 moods, 31 subgenres, and 63 antagonist types were randomly combined; one for each page for a total of 100 dark writing prompts. Titles of existing movies belonging to each mood/subgenre/genre/antagonist combination are listed to further inspire the reader when available.