There’s a lot of weird, nasty, not entirely pleasant fey running through folklore. This is why I get so angsty with people who talk about faeries and the fey when what they really mean is Victoriana.
The fachen, for example, is a fey-like spirit from Scotland whose appearance is so terrifying that the sight of him is enough to give a man a heart attack. Possessing only half a body, the fachen has one long arm, a giant mouth, and a mane of feathers that sticks up. He is known to destroy orchards while dragging a chain behind him with his one arm. He is also known as Peg Leg Jack or Direach Ghlinn Eitidh.
The dullahan is a spirit from Ireland who is identified in part by his lack of a head. He rides a skeletal horse covered in old skins and carries his own head under his arm. The head is constantly looking around. He carries a whip made out of a human spine and carries funerary adornments like candles set in human skulls. The dullahan are not found of watchers, and may throw blood on humans who have seen them-this is sometimes interpreted as a death omen.
The saci most likely does not belong on this list, if only because he’s not technically European but he probably has European roots in the more modern tellings. The saci comes from Brazilian folklore and is presented as a one legged, black skinned young man in a red hat. He is a prankster spirit, engaging in the small acts of aggression and destruction that are commonly associated with these types of spirits-small thefts, minor destruction of property, and generally causing a havoc in a household. However, he is not actively malevolent and it is said that he will actually aid a person if they manage to take his hat away. He is most like a hybrid myth, picking up influences from local folklore, European folklore, and Christian and Muslim imagery to create the myth as it is today.