I need some new suggestions~ I just got done watching "Another". Let me say that was a really super amazing anime <3.. Also finished Mirai Nikki. Not really a horror or mystery but if you know any animes like that please tell me~! Also any Yandere animes would be nice~
Higurashi no Naku Koro ni <------ HIGHLY RECOMMENDED (plus the other higurashi series, yandere) Gantz Deadman Wonderland - AMAZING!! Umineko no Naku Koro ni (ok..) School Days <---- also highly recommended, yandere Liar Game (manga) Death Note (obviously) Blood+ Elfen Lied Le Portrait de Petit Cossette (very strange and extreme, more artistic and thought-provoking) Darker than Black (literally the most amazing thing ever, more action, superpower but strong mystery and some horror themes) What is Another about?
Urm Fate/Stay Night is a fighting/mystery one As above Higurashi no naku koro ni is one of the best horror/mystery animes i have ever seen.. Um Shikabane Hime is another Horror/Mystery type Anime Also High school of the dead is a good horror one.
I'll add Ghost Hound and Ghost Hunt to the list, also possibly Shiki might work though I haven't seen it.
Elfen Lied (unforgettable story) High School of the Dead (a bit of a cliffhanger in the end, but the whole thing was good)
I wouldn't really recommend School Days; the only part that had anything close to horror was the ending. (Nice boat!) The rest of the anime is kinda meh. Higurashi is a really great horror/mystery. But in order to actually get it, you have to endure the repeats and watch Kai (second season). It's really good and I highly recommend it. Higurashi Rei ("third season") and...Kira ("fourth season")...are OVAs that aren't really required. High School of the Dead is another good one, but if you aren't a fan of fan service I wouldn't watch it. If you can ignore it, it's pretty good. Bold: Another - MyAnimeList.net
Well, I haven't watched much anime, but I have watched Higurashi and Umineko No Naku Kori Ni and they're probably my favorite animes! Sucks that they discontinued Umineko (as far as I know). But yeah, those two are great.