I'm very fond of the horror genre, but I can't find

Aoi Bungaku Series, Haven't got round to watching it myself but might be what your looking for.

Really you can't expect a whole lot from anime when it comes to horror. Probably best you can get is elements of horror in titles that are not explicitly horror, rather than searching specifically for it.
As recommended Aoi Bungaku is one.
Try Lain, one of the best examples I've encountered in fiction to evoke a feeling of paranoia.
Texhnolyze maybe (really more super oppressive than scary but beggars can't be choosers).
I suppose Shinsekai Yori could be said to have horror elements. Don't go expecting constant scares though. Pretty great anime otherwise but take this recommendation with a grain of salt.
If you can count thriller/mystery then Perfect Blue and Paranoia Agent from Satoshi Kon.
People often say Monster is scary. I like it a lot but personally didn't really feel it that much. It's worth a look into in any case though.

For "actual" horror there's Ayakashi and it's spinoff Mononoke.

For manga, Hideshi Hino is a classic author. Try also Fuan no Tane and Left Hand of God Right Hand of Devil.
Suehiro Maruo is amazing. Mind, it's mostly ero guro, in case that isn't your thing.

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I haven't seen it but I've heard Shiki is decent

>>307183
>I want to be disturbed

Kago Shintaro.

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>>307183

Iczer-1
Wicked City
Genocyber

Those are the only worthwhile horror anime.

Seriously, don't bother with anything else unless you're up for some major cringe. There might be better offerings for manga but I'm not quite sure myself.

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>>307183
https://www.youtube.com/watch?v=_O8ijfNpidU

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>>307183
The Kurosagi Corpse Delivery. The series follows five recently graduated university students who have formed a company which specializes in dealing with the dead and their last wishes.

It has horror and a lot of dark humour.

>>307183
Cossette no Shouzou

The anime is a brief introduction to the series but is a lot more cryptic and surreal

The manga is more extensive but is much less abstract and unfortunately it falls victim to a lot of tropes and conventions, but it's not awful

I'd say watch the anime for sure for the amazing infernal imagery, read the manga if you like what you see