In Goblet of Fire fanfiction, there are various plotlines related to Dark Harry. One is that he becomes a sort of anti - hero. He still opposes Voldemort but in a more morally ambiguous way. He may use methods that are frowned upon by the wizarding society. Another plotline could involve Dark Harry's interaction with the magical creatures in a different way. Instead of befriending them like in the original, he might use them for his own gain or experiment on them with dark magic. And sometimes, there is a plotline where Dark Harry forms his own group of followers, not quite like the Death Eaters but a group that follows his more radical ideas and they create chaos in the wizarding world.
One common plotline is Dark Harry competing in the Triwizard Tournament with a more devious approach. Instead of just trying to survive and win fairly, he might use dark magic to outwit his opponents. Another is his relationship with the Death Eaters. He could be in a situation where he is being courted by them, and he has to decide whether to join or resist.
A frequent plotline is Dark Harry's internal struggle. He may be constantly fighting the dark impulses within him. For example, during the tasks of the Triwizard Tournament, he might be tempted to use dark magic to make things easier for himself. Also, there could be a plotline where Dark Harry discovers secrets about his past that lead him further down the dark path. Maybe he finds out that there are hidden powers in his family history that are related to the dark arts and he starts to explore them.
In some fanfictions, a great plotline could be Harry and Luna forming a closer bond because of the Goblet of Fire chaos. Luna could be the one to comfort Harry when he's facing the difficulties and dangers of the tasks. And together, they might even uncover a conspiracy among the teachers or judges that was meant to manipulate the results of the Triwizard Tournament.
One interesting plotline could be Daphne and Harry teaming up secretly to investigate the mystery behind the Goblet of Fire. Maybe they suspect some dark magic interference that others haven't noticed yet.
One interesting plotline could be Draco secretly helping Harry during the Triwizard Tournament. Maybe he has a change of heart and realizes that the dark side isn't what he really wants. Another could be a friendship forming between them in the face of a common enemy within the tournament. For example, a dark wizard who tries to manipulate the tasks for their own evil purposes.
One possible plotline could be a friend betraying Harry to gain favor with the Death Eaters. Maybe they leak information about Harry's tasks in the Triwizard Tournament. This would add a whole new layer of danger and drama to the story.
A plotline could involve a dark assassin who has a personal vendetta against a particular wizarding family. They start by targeting the family members one by one, and the family has to enlist the help of Harry and his friends to stop the assassin. This often involves delving into the family's past to find out why the assassin is after them.
One possible plotline could be how Harry copes with the unexpected summons. Maybe he has to deal with the distrust of his friends who suspect him of somehow cheating the Goblet. Another could be his training in secret for the tasks, perhaps with the help of an unlikely ally.
One interesting plotline could be a different take on the Triwizard Tournament tasks. Maybe the challenges are not as straightforward as in the original, with hidden twists and alliances among the champions that we don't see in the book. For example, the champions might have to work together in some tasks secretly to overcome a greater threat that the judges don't know about.
One common theme is friendship. Since Harry and Susan are the main focus, their relationship often develops into a strong friendship in these fanfictions. Another theme is the exploration of the Triwizard Tournament from a different perspective. With Susan added to the mix, the events of the tournament can be seen in new ways.
One interesting plotline could be Hermione and Fleur teaming up to solve a mystery within the Triwizard Tournament. They might use their combined intelligence and skills. For example, Hermione's vast knowledge of magic and Fleur's charm and unique magical abilities could be a great combination to figure out a dark plot against the champions.
Yes, it can be a somewhat common theme. In fanfiction, writers often explore different relationship dynamics that weren't fully developed in the original 'Goblet of Fire' story. Some fans might be intrigued by the idea of Hermione and Harry having a more romantic connection, so they write about Hermione kissing Harry to create new and interesting storylines.