Well, I usually find great Harry x Hermione fanfictions related to the Triwizard Tournament on some Harry Potter fan forums. People there often share their favorite stories or even write their own. You might have to dig a bit, but it's worth it. Some of these fanfictions can offer really interesting takes on their relationship during that event.
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.
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 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.
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.
You can try searching on fanfiction websites like Fanfiction.net or Archive of Our Own (AO3). On Fanfiction.net, use the search bar and type in 'Werewolf Harry x Hermione'. AO3 also has a great search function. Just make sure to read the tags and summaries to find the ones that suit your taste.
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.
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.
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.
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.
One good fanfiction could be 'The Triwizard Aspect Adventure'. In this, the magical elements of Harry Potter's Triwizard Tournament are combined with the Aspects from Warcraft. It creates a unique world where Harry and his friends encounter Warcraft - like creatures during the tasks of the tournament.