Sure. One might be a story about a person who slowly loses their sanity in a desolate, old house where strange noises keep them on edge every night. Another could be a tale of a character who discovers a hidden and very dark secret about their family that completely shatters their view of the world.
Often, it's the unexpected and dark twists. For example, in some of these stories, characters that seem normal at first turn out to be capable of great evil. It goes against our expectations of how people should behave.
One common element is the unknown. For example, in many short disturbing stories, there are strange noises or movements that can't be easily explained. Another is the presence of something that seems out of place, like a doll with a creepy look or a strange symbol. Also, a feeling of being watched is often included, which makes the reader or listener feel uneasy.
Once there was a little girl who found a doll in the attic. The doll's eyes seemed to follow her everywhere. At night, she could hear faint whispers coming from the doll. One day, she noticed the doll had a strange mark on its back, like a symbol she'd never seen before. It gave her the creeps, but she couldn't bring herself to get rid of it.
One common theme could be isolation. Many disturbing stories use isolation to heighten the sense of fear and unease, like a character being alone in a big, empty place. Another might be the loss of sanity, as it makes the reader wonder what they would do in such a situation.
There's a story where a young girl befriends a stray cat. But soon, she realizes the cat has a strange mark on its back. As she investigates, she discovers that the cat seems to be a part of some sort of dark experiment in the neighborhood. The people involved start to target her when they find out she knows their secret.
You might consider publishing them on specialized horror or thriller fiction platforms. Some websites are dedicated to such genres and attract the right audience for such content.
One is 'The Yellow Wallpaper' by Charlotte Perkins Gilman. It's about a woman's descent into madness as she is confined to a room with the eponymous wallpaper. The story is dark as it shows the oppression of women's mental health in a patriarchal society.