Creepy but realistic books

I just read an AskReddit post that asks “What do you SWEAR you saw but don’t have any proof of?” I’m not sure if I’m allowed to link it.

The stories were mostly on the creepy side and some of them felt like they could continue into a whole book. I liked the fact that they all seemed possible since they supposedly happened to people but not over the top with monsters or crime. Just an eerie feeling throughout. I think We Have Always Lived in the Castle sort of has that vibe, wondered if people had more suggestions.