What are interesting plot twists for a novel?

Twists could include showing that a character who was thought dead is actually alive, or maybe revealing that a trusted character is actually a villain. Thrillers can use natural disasters or freak accidents to put characters in peril. Mystery novels can introduce new evidence that redirects suspicion or dramatically increases the scope of an investigation. New romantic relationships between characters can also add interesting twists. Novels can also use unreliable narrators to show that information has been withheld from the reader.