looking for the scariest stories you know
Hell App - https://www.novelupdates.com/series/hell-app/
Probably the closest one of these novels has come to genuinely unsettling me.
My House of Horrors - https://www.novelupdates.com/series/my-house-of-horrors/
Most enjoyable horror novel for it's novel ideas. Lots of great horror storytelling. Mainly ghost stories.
Plague Doctor - https://www.novelupdates.com/series/plague-doctor/
Once again, top quality horror descriptions.
Those are the ones that I loved. There are lots of others, but I didn't really care for them. Some people like Thriller Paradise.
I haven't seen a lot of horror on RR specifically, but I can recommend these two:
Keep Breathing is similar to a particular classic staple of the horror genre (no spoiling which) with a unique twist. It has fantastic characterisation, is very well written, and generally a good, solid read. I didn't find it particularly frightening, personally, but it's definitely a horror story and I can give it a strong recommendation.
My Delirium Alcazar is one of the weirdest genre-blurring stories you're likely to find on RR, with strong horror elements (including both psychological and body horror). It's fun and compelling with sympathetic and relatable characters, and heavy helpings of gamelit, surrealism and mystery thrown in to boot. Another very strong contender.
No joke, it was so scary (esp with the recommended song) that I couldn't finish the first chapter, even with the compelling synopsis and excellent writing, it was just too much.
Lots of body horror and eldrich abominations. Also maybe the single best web fiction I've ever read.