A great fanfiction idea could be that Hermione enters the Triwizard Tournament instead of Cedric. Harry then becomes her biggest supporter. They train together, and Hermione uses her intelligence to come up with unique strategies for each task. During the Yule Ball, instead of Ron being jealous, he helps them prepare for the upcoming tasks, and they all grow closer as friends through the whole experience.
One possible fanfiction could be about Harry and Hermione teaming up secretly during the Triwizard Tournament tasks. They might use their combined knowledge and skills to outwit the other competitors. For example, in the maze task, they could have a special code to communicate and find their way to the Triwizard Cup faster than anyone else.
In a fanfiction, Harry and Hermione could face a lot of challenges during the Triwizard Tournament that are not in the original story. Maybe there's a dark magic spell cast on the tournament by a rogue wizard, and they have to figure out how to break it while still competing. They would rely on their friendship and loyalty to each other to get through these tough situations.
There might be a fanfic where during the Triwizard Tournament, Harry gets cursed and Hermione has to find a way to break the curse. She races against time, using every spell and potion she knows. Meanwhile, she also has to deal with the tournament tasks on Harry's behalf. In the end, through her determination and love for Harry, she manages to break the curse and they both complete the tournament in an unexpected way.
One possible scenario in this fanfiction could be that Harry and Fleur form an unexpected alliance during the Triwizard Tournament tasks. They might discover they have complementary skills, like Harry's courage and Fleur's elegance and magic related to water (since she's from Beauxbatons). This alliance could lead to them facing the challenges in a new and interesting way, perhaps with Fleur using her Veela charm in a creative manner to distract the obstacles while Harry uses his Gryffindor bravery to take on the more physical parts of the tasks.
There are fanfictions where Hermione and Fleur become friends during the Triwizard Tournament. In some stories, they start to see past their initial rivalries. Fleur might initially see Hermione as just a book - smart girl, but as they face the challenges of the tournament together, they develop a mutual respect. Maybe they work together on the Yule Ball preparations within the context of the tournament, which helps to strengthen their bond.
In some fanfictions, the author might explore the idea that the person who dragged Harry into the Triwizard Tournament has a personal vendetta against him. Maybe it's a relative of a Death Eater who wants to see Harry fail publicly or even die during the tournament. Harry then has to not only survive the tasks but also figure out who is behind this plot against him.
One possible fanfiction could be about Harry getting amnesia during the Triwizard Tournament and Luna being the one to help him remember. Maybe she uses her unique perspective and knowledge of magical creatures and odd things to jog his memory. For example, she might take him to see the Thestrals, which are associated with death and memory in the wizarding world.
The fanfiction could take an interesting turn if the dark elf part of Harry was somehow tied to the origin of the Triwizard Tournament. Perhaps there was an ancient dark elf magic involved in the creation of the tournament, and Harry, being part dark elf, has a special connection to it. He could then uncover secrets about the tournament that no one else knew, which could give him an edge in the tasks.
One great fanfiction could be where Harry and Luna team up in a unique way during the Triwizard Tournament tasks. Maybe Luna uses her off - beat magical knowledge to help Harry solve the puzzles in the maze. For example, she might recognize some magical creatures that Harry is unfamiliar with and guide him through.
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.
A plot twist could be that the Triwizard Cup is actually a portal to a different dimension, and Harry and Hermione accidentally get transported there during the final task. They then have to find a way back while dealing with strange creatures and magic in this new dimension.
Harry and Ron would be her most likely allies. They are her best friends, and even if they might be initially shocked or jealous of her being in the tournament, they would surely come around to support her. Another likely ally could be Cedric Diggory. He's a fair - minded and kind wizard, and he might see Hermione's intelligence and skills as an asset and offer to help or at least be friendly towards her.