Recs if you like Final Girls...

Speculative (sci-fi, fantasy, horror etc.) novellas less than 200 pages long that are either standalone or read like a standalone story

Horror books with a page count of 200 pages or less.

Before we started defining novellas by word count, they were defined as being any book less than 200 pages. Source: my Analysis of Short Stories & Literature professor in community college. I loved that class. But he loved James Joyce. So, ymmv, I guess.

What it says on the tin