Here's a list of horror films I've reviewed on Letterboxd. I'm only reviewing things as I watch/rewatch them so it's nowhere near looking anything like my actual list of favourite horror films. Give me a few years.
Films qualify for this list if they are tagged as horror. I'm not serving as the judge of whether something is or is not horror. I have, on the other hand, made the decision that I'm only including narrative features and full-length movies at least 41 minutes long (in keeping with Letterboxd's dividing line for features and short films.) No documentaries or short films.