A really cool plot twist could be that the Hogwarts founders are not as dead as everyone thought. They have been in a sort of magical stasis far from Hogwarts. Harry stumbles upon them during his travels very far from home. They have different views on how magic should be used compared to modern wizards. Harry then has to decide whether to side with the founders' old - fashioned ways or stick to what he has learned at Hogwarts, all while being in a strange and unfamiliar place.
Often, there are original characters who are powerful witches or wizards that befriend Harry on his journey very far from home. For example, there might be a young witch named Luna (not the same as the one in the original books) who has the power to control the elements. Another popular type is a wise old wizard who gives Harry cryptic advice and helps him along the way.
One interesting plot twist could be that Peter Parker's identity as Spider - Man is revealed to the public in a much more dangerous way than in the movie. Maybe a villain uses some mind - control device on someone close to Peter and forces them to expose him at a really bad time, like during a big public event where all the Avengers are present.
One interesting plot twist could be that Jasper's vampire abilities are used to protect Harry from a new and unexpected dark magic. For example, Jasper might be able to sense a dark wizard's intentions before they attack Harry. Another twist could be that they discover a hidden connection between the wizarding world and Jasper's vampire world, like a shared ancient magic that only they can unlock together. It could also be that Jasper's ability to control emotions helps Harry deal with his own inner turmoil caused by Voldemort's presence, in a way that no one else in the wizarding world can.
One interesting plot twist could be when a character who was originally a minor antagonist in the original series becomes a key ally in the 'back to the past' scenario. For example, in some fanfictions, Draco Malfoy might end up joining Harry's side early on, changing the whole dynamic of the story. Another could be when a major event from the original series is prevented, like Sirius Black's death. This creates a whole new set of consequences and relationships that the author can explore. And sometimes, the way magic is used in these fanfictions can be a plot twist. Maybe a character discovers a new type of magic that wasn't in the original books, which gives them an unexpected advantage in the 'back to the past' world.
In some fanfictions, a big plot twist is that Jacob turns out to be related to one of the major wizarding families in the Harry Potter universe. This completely changes his status and the way other characters interact with him. It adds a whole new layer of drama and mystery to the story.
Some fanfictions might explore the multiverse aspect more. In a 'Spider - Man: Far From Home' fanfiction, Peter could accidentally cross into a different version of the Marvel Universe where things are very different. For instance, Tony Stark might still be alive but has become a villain, and Peter has to figure out how to deal with this new reality while still trying to get back to his own universe.
Well, in this fanfiction, a possible plot twist might be that the prophecy about Harry was misinterpreted all along. Instead of him being the only one to defeat Voldemort, there are actually others with the same potential. Also, what if the Dark Mark has a secondary, unforeseen purpose? And a really cool twist could be that some of the teachers at Hogwarts have a much more complex backstory than we thought, and they are involved in some shadowy affairs that change the whole dynamic of the story.
Perhaps a plot twist could be that the Ministry of Magic tries to interfere with Harry's pregnancy because they fear the implications it might have on the wizarding society. They could try to force Harry into hiding or even attempt to separate him from Charlie. However, Harry and Charlie, with the help of their friends, fight back against the Ministry's unjust actions. This would not only create a lot of drama but also show the strength of their relationship and their determination to protect their family.
One interesting plot twist could be that Harry discovers he has the ability to communicate with the Basilisk on a deeper level than just Parseltongue. Maybe he can see through the Basilisk's eyes and use this to his advantage in uncovering secrets within Hogwarts that even Dumbledore doesn't know. Another could be that the Basilisk is not truly a villain but was being controlled by a dark force all along, and Harry has to find a way to break that control and free the Basilisk.
One interesting plot twist could be that the basilisk has an unexpected alliance. Maybe it teams up with a group of outcast magical creatures to take revenge on those who have wronged them. This would completely change the dynamic as in the original, the basilisk is mainly a tool of Voldemort.