A really cool plotline could be that the Triwizard Tournament tasks are all connected to an ancient prophecy that only Harry and Susan can figure out. They start to notice strange symbols during the tasks that lead them on a hunt through Hogwarts' secret passages to uncover the truth behind the prophecy.
One common plotline is that Hermione participates in the Triwizard Tournament instead of Cedric. This gives her and Harry a whole new dynamic as they face the challenges together. Another plotline could be that there's some sort of magical interference during the Tournament that makes Harry and Hermione realize their deeper feelings for each other. For example, a spell gone wrong that makes them share their innermost thoughts.
Another possible antagonist could be a jealous student. Maybe someone who was not chosen for the Triwizard Tournament and feels left out. They might try to sabotage Harry and Susan's chances in the tournament out of envy.
A possible plotline is that Luna enters the Triwizard Tournament as an unexpected champion. Harry, already in the tournament, teams up with her to face the challenges. They use their combined skills, Harry's Gryffindor courage and Luna's Ravenclaw wisdom, to overcome the tasks.
A common plotline is that of Hermione and Fleur teaming up against the other competitors. This is interesting as it subverts the expected rivalry. They can use their combined strengths to overcome challenges that neither could face alone. For example, Hermione's strategic thinking paired with Fleur's beauty - based magic can be a formidable combination in tasks like the maze.
One idea could be a different champion from an unexpected school. For example, a small wizarding school in a far - off land sends a champion. This champion could have unique magic abilities that are not common in Hogwarts, Beauxbatons, or Durmstrang. They might use magic related to nature in a very different way, like communicating with magical plants to solve tournament tasks.
One idea could be a story where a new, unexpected champion enters the Triwizard Tournament. Maybe a student from a different magical school that we haven't heard of before. This new champion could bring unique magic and challenges to the tournament, causing all the other champions to have to adapt their strategies.
There could be a plot point where Fleur's Veela heritage causes problems during the tournament. For example, it might attract unwanted attention from some of the creatures in the tasks, like the dragons in the first task. Harry has to use his quick thinking to protect Fleur and keep her focused on the task at hand. This could lead to some comical as well as intense situations as they try to deal with the chaos caused by her Veela charm.
Perhaps in the fanfiction, Fleur could be in danger during one of the Triwizard Tournament tasks. Harry, being the heroic type, decides to risk everything to save her. This act of heroism not only changes their relationship but also how the other champions and the judges view Harry. It could also lead to some changes in the overall dynamic of the tournament, like new rules being implemented to prevent such dangerous situations in the future.
One idea could be to cross it with the world of Narnia. Imagine the Triwizard champions having to face challenges in the magical land of Narnia. They might have to deal with the White Witch's minions or find their way through the enchanted forest. Another idea is a crossover with the Percy Jackson universe. The demigods could participate in the Triwizard Tournament, bringing their unique powers and abilities. For example, a son of Poseidon might use his water - controlling powers in a water - based task.
One interesting plot could be a character who is an underdog in the academic Triwizard Tournament. They might not be as well - known or as powerful as the others at first. But through their hard work, they discover a unique magical ability that gives them an edge in the challenges. For example, they could have a special connection to an ancient magic that helps them solve a difficult riddle in one of the tournament tasks.