One good twist could be a character who seems to be the villain turns out to be the hero all along. For example, in a detective story, the suspect who has all the signs pointing to him as the killer is actually trying to protect the real victim from a more dangerous threat.
One example is in 'The Sixth Sense' where the twist is that the main character is actually dead all along. This completely changes the way the audience views the entire story.
One good plot twist could be that the character who seems to be the hero is actually the villain all along. For example, in a detective story, the detective who has been leading the investigation turns out to be the mastermind behind the crimes he's supposed to solve. It completely flips the reader's expectations.
One good twist could be a character who seems to be the hero turns out to be the villain all along. For example, in a mystery short story, the detective who is leading the investigation is actually the mastermind behind the crime. He has been manipulating the evidence and leading everyone astray.
One good plot twist could be that the person the main character thought was their soulmate turns out to be a long - lost relative. It completely changes the dynamic of the relationship and adds a whole new layer of complexity and drama. For example, they might have been on the verge of getting married when this revelation comes to light.
Another way is by withholding crucial information until the right moment. In a mystery story, the writer might not reveal the true identity of a key figure until the end. This builds suspense and makes the twist more impactful when it's finally revealed. Also, subverting expectations can create great twists. If the readers expect a character to act in a certain way based on the story's setup, but then the character does the opposite, it can be a very effective twist.
The discovery that the entire world the characters live in is a simulation. In a short science - fiction story, the characters are going about their normal lives until they start to notice glitches in the world around them. As they dig deeper, they find out that their whole existence is just part of a complex computer - generated simulation, which turns their understanding of reality upside down.
One good plot twist could be that the two characters who seem to be falling in love are actually long - lost siblings. It completely changes the dynamic of their relationship from romantic to a more complex family - oriented one.
Character development plays a role too. If a character has a hidden side that is revealed as a plot twist, it should be consistent with their previous actions and personality to some extent. For example, in 'Shutter Island', Teddy's true identity as a patient rather than an investigator is a major plot twist. But looking back, his strange experiences and mental states on the island can be seen as clues, and his character's journey makes the twist feel more earned.
One good plot twist could be that the main character, who has been searching for a missing heirloom throughout the story, discovers that it was in their possession all along, hidden in a place they never thought to look. Maybe it was inside an old family photo album that they never fully explored.