As far as I can tell, the oldest folklore monster in history is the revenant. The English Abbot of Burton wrote about two around the year 1090, although he didn’t call them revenants.
John Polidori probably based his novel, “The Vampyre” (published in 1819), on a revenant. “Dracula” wasn’t published until 1897. The zombie was first written about in 1819. Modern zombies are mostly based on the horror movies by George A. Romero, which were based mostly on the “I Am Legend” novel.
The Wikipedia page doesn’t list what I consider the best example of the revenant, a 2009 film. It shares the same title as the 2015 film, but the 2015 film tells the story of someone who should have died and didn’t.
There are more examples in fiction, one of the latest being the TV incarnation of “American Gods”. I read the book it’s based on years ago, a few years after it was published. The book is still sitting in one of my closets. The first season of “Wynonna Earp” focused on sending revenants back to hell.
I used to like reading horror fiction. I also used to like watching horror movies. These days, horror stories turn me off. The television and movie industries have milked vampire and zombie stories to death, pardon the pun.
I’m more interested in the history of the monsters depicted in horror fiction. More precisely, why did people think someone was a revenant or a vampire? Were they seeing the effects of some disease or were their minds playing tricks on them? Did superstition take over when no other reasonable explanation existed?
I’ve heard a lot of horror stories while living in the Philippines. Most of them are about one form of aswang or another. Some of them are about ghosts like the white lady. Filipinos are very superstitious, even those who’ve lived in urban areas all their lives. Don’t make fun of a Filipino who truly believes in certain creatures, or you could end up with a lifelong enemy. I’ve been smart enough to keep my mouth shut for a very long time.