There is 'The Call of Cthulhu' by H.P. Lovecraft. It's a story full of cosmic horror. The main character discovers an ancient and malevolent being, Cthulhu, that exists outside of normal human understanding. The very idea of this being and its potential to awaken is extremely horrifying. Another horror short story is 'The Black Cat' by Poe. A man's descent into alcoholism and madness leads him to mistreat and ultimately kill his cat, only to be haunted by a new cat that seems to be a reincarnation of the first. 'August Heat' is also a horror short story where a man on a hot day has a series of strange encounters that seem to predict his own doom.
One very horror short story is 'The Tell - Tale Heart' by Edgar Allan Poe. It's about a narrator who is haunted by an old man's vulture - like eye and eventually kills him. The guilt drives the narrator to madness as he imagines he can still hear the old man's heart beating even after the murder. Another is 'The Monkey's Paw'. A family gets a magical paw that grants wishes, but each wish comes with a horrible and unforeseen consequence. The third one could be 'The Yellow Wallpaper'. It shows a woman's descent into insanity due to her confinement and the strange patterns on the wallpaper.
There's 'The Monkey's Paw' which is a great horror very short story. It involves a family who comes into possession of a magical monkey's paw that can grant wishes, but each wish comes with a horrible price. Also, 'The Yellow Wallpaper' by Charlotte Perkins Gilman can be considered. It's about a woman's descent into madness while being confined in a room with yellow wallpaper.
One very short gothic horror story could be 'The Doll'. In a dusty attic, a little girl finds an old porcelain doll. Its eyes seem to follow her. At night, she hears faint giggles. When she wakes, the doll is on her pillow, its cold porcelain face inches from hers.
Sure. One could be about a creaking door in an old house that always opens at midnight by itself, and no one knows what lurks behind it.
Sure. Here's one: The old house was empty for years. I heard a baby crying from inside. I entered, but there was no one. Then I realized the crying was coming from the walls.
There is a horror story about a werewolf. In a small village, people started disappearing at night. It turned out that a werewolf was on the loose. The descriptions of the werewolf's attacks are extremely horrifying.
The last person on earth sat alone in a room. Then there was a knock at the door.
One short horror story is about a girl who woke up in the middle of the night to a strange dripping sound. She followed it to the bathroom. As she opened the door, a cold hand grabbed her ankle from the dark bathtub. She screamed but no one heard her.
Sure. Here is one: 'The Little Star. A little star was lonely in the sky. One night, it made a wish. It wished to be friends with the moon. And then, its wish came true.'
Sure. One might be 'The Haunting of Blackwood Manor' which was quite popular in 2018 horror short stories. It had a really creepy atmosphere with a haunted house setting and strange noises in the night.
One short horror story could be 'The Bus Stop'. A woman waits at a lonely bus stop late at night. Every time a bus comes, the driver just shakes his head and drives on. Finally, an old bus arrives and the door opens. Inside, she sees all the passengers are pale and motionless, and as she steps in, the bus drives into the darkness.