Well, one interesting plotline could be that the twin sons are sorted into different houses. This causes a bit of a stir in the wizarding world as people expect them to be in Gryffindor like their father. But one ends up in Ravenclaw, for example. This leads to them having different groups of friends and different perspectives on magic. They then have to work together to face a new threat to Hogwarts, which tests their loyalty to each other and to their respective houses.
A great plot could be centered around their relationship with their parents. Since Harry had a difficult childhood, he might be overprotective of his sons. The twins could struggle with this overprotection while also trying to make a name for themselves at Hogwarts. Also, they could be involved in a mystery related to the Dark Arts that resurfaces, and they use their combined skills to solve it, all while dealing with the pressures of being Harry Potter's sons.
One interesting plotline could be the twins getting involved in a time - traveling adventure within the wizarding world. They might use their signature prank - skills to outwit dark wizards in different eras.
A possible plotline is that the twin was separated from Harry at birth for some mysterious reason. Maybe a dark wizard wanted to use the twin's power for his own evil purposes. Years later, when they meet at Hogwarts, they don't recognize each other at first. But as they start to get to know each other, they sense a strange connection. This discovery could then lead to a journey of uncovering their past and their true family history. Along the way, they would face many challenges together, both from within the school and from the outside forces that are still interested in the twin's power.
One interesting plotline could be the twin sister having a unique magical ability that Harry doesn't. For example, she might be able to communicate with magical creatures in a way no one else can. This could lead to her getting involved in adventures that are separate from Harry's at Hogwarts, but still end up being connected in some way, like when she discovers a secret about a creature that is related to a dark wizard who is also after Harry.
One possible plotline could be Harry struggling to hide his Tourettes symptoms at Hogwarts in the beginning. He might be afraid of being judged by his classmates. For example, during a Potions class, his tics could cause him to accidentally add the wrong ingredient, leading to a minor magical mishap. Another plotline could involve Harry using his magical abilities to find a way to manage his Tourettes better. He could go on a quest to find a rare magical herb or spell that helps him control his tics. Also, his friends like Hermione and Ron could play a big role in supporting him, learning about Tourettes, and standing up for him when others are unkind.
In a fanfiction about Harry Potter having diabetes, there could be a plot where Harry discovers a new type of magic that is related to his condition. Maybe he finds that certain spells can help him better manage his blood sugar levels. His relationship with the Hogwarts staff could also be explored. For example, Madam Pomfrey might be at a loss at first as she's used to dealing with more typical wizarding ailments. But then she works with Harry to come up with a plan to keep his diabetes in check. This could also lead to a greater understanding of muggle diseases in the wizarding community.
One interesting plotline could be the twin sister using her unique bond with Harry to help him in his battles against Voldemort in ways that others can't. For example, she might have a special magical ability that is only enhanced by their twin connection.
One interesting plotline could be the twin sister having a special magical ability that Harry doesn't. For example, she might be able to communicate with magical creatures in a way no one else can. This could lead to her getting involved in adventures that help Harry in his fight against Voldemort in a different way than in the original books.
One possible plotline could be the constant bickering between Harry and his twin which adds a new layer of family drama to the wizarding world. For example, they might compete for attention at Hogwarts, creating humorous situations in the classroom or during Quidditch matches.
One interesting plotline could be the twin sister having hidden magical powers that are different from Harry's. For example, she might have an affinity for ancient spells that have been long forgotten in the wizarding world. Another could be that she was separated from Harry at birth due to a prophecy that the dark forces were after her specifically, and she grows up in a different magical community, unaware of her true identity until later in the story.
In a more detailed plot, Harry's newfound eagle vision might be a side - effect of a powerful spell gone wrong. He initially struggles to control it, seeing things that are too far away or too detailed all at once. As he learns to master it, he realizes it gives him an edge in Quidditch. He can spot the Snitch from an incredibly long distance, making him an even more formidable Seeker. This also draws the attention of the opposing teams who try to find ways to counter his new ability.