A plot might be about Harry's child struggling with the pressure of living up to their father's legacy. At Hogwarts, they constantly feel compared to Harry. But then, they find their own niche in the wizarding world by being really good at potion - making. They enter a big potion - making competition and end up using their skills to save the day when a dark potion goes wrong and starts affecting students. They prove that they can be great in their own way, not just because they are Harry Potter's child.
One possible storyline could be that the child is a result of a relationship Harry had during his later years at Hogwarts that was kept secret. Maybe it was with a foreign witch he met during one of his adventures outside of Hogwarts. The child could inherit Harry's magical abilities and also some of his personality traits like his courage and sense of justice. Then the story could focus on how the child discovers his or her true identity and the legacy of being Harry Potter's offspring.
Perhaps the plot could be that the child of Harry Potter gets sent back in time accidentally. There, they meet a young Harry and his friends. The child has to be very careful not to disrupt the past too much while also trying to find a way back to their own time. This would be filled with lots of tricky situations, like when they almost reveal future events or when they have to avoid being seen by their own young parents.
One possible plot could be that Harry was seriously injured in a dark magic attack. The feeding tube is a result of his inability to eat normally due to the damage to his body. He has to struggle not only with the physical pain but also with the stigma in the wizarding world where such a medical device might be seen as a sign of weakness. Meanwhile, his friends try to find a magical cure to get rid of the need for the feeding tube.
One possible plot could be that Harry Potter, through some magical mishap or powerful spell, is transformed into a bride. Maybe he has to go on a quest to find a way to reverse the spell while dealing with the strange reactions of his friends and the wizarding world. For example, Ron might be completely confused and Hermione would be trying to find a solution in the library.
Well, it could be about a character in the Harry Potter world who discovers that a child is theirs and not someone else's. Maybe it's a story of a wrong assumption of paternity, and the real parent has to fight to claim the child. For example, a wizard who was wrongly thought to be the father by another wizard, and through a series of magical adventures and revelations, the truth comes out.
One possible plot could be that Harry's daemon is a key to his hidden powers. It could be a unique form, like a phoenix - like daemon, which gives him an extra connection to Dumbledore's phoenix. The daemon could help him in battles by sensing danger before he does and guiding his magic in a more intuitive way.
Well, perhaps the tattoos could be a mark of a secret society within the wizarding world that Harry gets involved in. They might give him special powers or knowledge.
Well, one possible plot could be that Dudley gets into some kind of trouble or situation where he can't take care of his child. Harry, having grown into a kind and responsible person, steps in. He might introduce the child to the wizarding world in a gentle way, teaching the kid about magic and also about the importance of family values. The story could also involve the child struggling to fit in both the Muggle and wizarding worlds, with Harry as their guide.
It could be a new dark wizard who is jealous of Harry Potter's fame and success. This dark wizard targets Harry's child, thinking that by causing trouble for the child, they can somehow diminish Harry's reputation in the wizarding world. He might try to frame the child for various dark magic incidents around Hogwarts.
A plot could be where Tracey Davis is wrongly accused of stealing an important magical artifact from the school. Harry believes in her innocence and sets out to prove it. Along the way, they find out that there's a much larger conspiracy at play involving some of the other Slytherin students and a group of dark wizards. As they dig deeper, their friendship grows stronger as they face numerous challenges and dangerous situations.