Sibyl

Lady Sibyl Crawley is the youngest daughter of Robert and Cora Crawley in the television series “ Downton Abbey”.

Sibyl is an antagonist in the anime "Psycho Pass". "The Sibyl System", used for law enforcement, is named after them.

Actually, the Harry Potter character's name is Sybill Patricia Trelawney, though in 'Harry Potter and the Order of the Phoenix' her first name is misspelled as 'Sybil'. Her name was also misspelled as 'Sybil' on the box for her collector character wand.
http://harrypotter.wikia.com/wiki/Sybill_Trelawney.

Sybil Ludington is a heroine of the American Revolution. She is called the 'female Paul Revere' because she rode 40 miles in darkness to warn American militiamen that the British were marching against Danbury, Connecticut. She was 16 years old at the time. She was congratulated by George Washington for her heroism.

In Oscar Wilde's only novel, "The Picture of Dorian Gray", Sibyl Vane is a young actress who becomes a victim of Dorian's sinful nature.

Sibyl Vane is an actress who is the object of the title character's infatuation in the novel The Picture of Dorian Gray. She poisons herself when he leaves her after she has given a bad performance.

Sibyl Trelawney is a Seer and Divination teacher in the Harry potter Books.

Her name isn't actually Sibyl Trelawney, it's Sibyll Trelawney.