I don’t consider many horror movies genuinely scary. The ones I have, at various times in my life, been actually in some way frightened (or at least shook) by, in no particular order:

• The Exorcist (The Version You’ve Never Seen)
• Hereditary (a masterpiece in my opinion. Free upvote literally every time I see someone recommend it)
• Blair Witch Project
• Paranormal Activity
• Ouija: Origin of Evil
• It (miniseries got me as a kid but Chapter 1 is good too)
• Lights Out (not the entire movie but it has its moments and overall a good style)
• Candyman (original)
• Poltergeist (original)
• Autopsy of Jane Doe (another poster reminded me of this one!)
• The Taking of Deborah Logan (for like one scene but IYKYK)
• The Dark and the Wicked
• The Orphanage
• Terrified and When Evil Lurks were both solidly unsettling at least
• Event Horizon (though I know you didn’t like this one)
• Conjuring 1-2 and Sinister too, all at least solid spookies.

Note that this does not mean these are the only GOOD horror movies. There are LOTS that I consider masterpieces that just aren’t strictly all that scary.

Cloverfield - not sure if thats horror

Frailty

Insidious

As a kid i loved the early Jason and Freddy movies.

I don’t get scared easily, but Kothanodi had me watching through my fingers. It has four vaguely connected stories, and two of them are very fucked up. There’s a decent amount of infanticide and other atrocities inflicted on minors, so be warned if you have any childhood trauma.

Also by the same director, the movie Aamis is about cannibalism acting as a replacement for sex. It’s pretty fucked up as well.

If you like the supernatural/demon ones, check out The Autopsy of Jane Doe. I loved it, the tension is absolutely perfect and a fantastic cast to boot.

If you want something a bit different, seek out Threads. It’s on the Internet Archive (here, in fact)

Not a traditional horror film at all, it’s set in the north of England in the early 80s (depending what n where you’re from, the accents might prove a challenge!) and shows the ordinary people of a small city gradually coming to terms with escalating tensions between East and West, which result in all out nuclear war.

And then we get to see the actual on the ground nightmare that that would be. Not in a showy Hollywood way but in a grim, horrifyingly real feeling gritty British drama way. Bleak isn’t the word.

It’s something that’s never quite left me since I saw it for the first and so far only time some years ago. Truly disturbing, and not fun at any point after things start getting serious. Brilliant though.

I’m pretty dead inside so not a ton can get through in the horror department, but I always thought 28 Days Later and 28 Weeks Later did a fantastic job making zombies a bit scary again.

Not sure how great it holds up today since it was a while ago I watched it last, but The Thing is for me still one of the best ones.

It Follows. It isn’t the best horror movie, but the premise is one of the scariest for me. An entity that is inevitable, and you cannot get away from no matter what you do or where you go. It’s always there, walking towards you.

The original Candyman.

Everything about it is excellent and holds up even now. The musical score is exceptional.

Don’t bother with the reboot. It has a message it’s trying to send, which I get, but they’ve done it to the detriment of the horror. Something could’ve been done with the premise but they fell short.

OG all the way.

Not a horror film per se, but definitely leaning that way:

The original ‘ALIEN’.

The building of tension throughout the entire movie is brilliant.

There is a particular type of emotion which “The VVitch” and “Hereditary” get absolutely perfect. It’s actually not really my favorite type of movie; it’s not particular scary, per se, but it is just some stuff that is really awful that you don’t want to see. If you don’t want that, they may not be good, but if you vibe with that particular emotion they are hard to beat for it.

The HBO “Chernobyl” miniseries is absolutely straight-up horror. It has pretty much all the elements of a perfect horror movie, except it’s (with tiny exceptions and artistic licenses) all 100% true.

“As Above, So Below” is fairly good “normal” horror of a fairly unspicy flavor.

That’s honestly all I can think of that really does it well. Horror books in my experience are far better. “The Shining,” “Pet Semetary,” “Night Shift,” and “Skeleton Crew.” Also lots and lots of HP Lovecraft; the “Dunwich Horror” collection is wonderful.

Hope this helps.

Drag Me To Hell was surprisingly scary and also just a good movie.

As Above, So below is reasonably solid

There’s a bit of a Mary Sue issue but otherwise good.