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.
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.
Perhaps there's a prophecy in both universes that foretells of a coming disaster that can only be averted by the combined forces of the wizarding world and Riddick. Riddick is drawn to the wizarding world because of some strange magic that he senses. Once there, he meets Harry Potter. At first, they don't trust each other. But as they face challenges together, like strange magical - mechanical hybrids created by a rogue wizard who has been experimenting with technology from Riddick's world, they start to respect and rely on each other, ultimately working together to save both universes.
One possible plot could be that some Hogwarts students go on an exchange program to a magical ranch in the American West. There, they meet cowgirls who are also witches. Together, they face a new dark magic threat that is affecting the ranch's magic. The transformation (TF) aspect could be that the Hogwarts students learn new spells from the cowgirls that transform the local magical creatures in unexpected ways.
Maybe Harry has faced so many traumas and disappointments in the wizarding world that he just decides to distance himself from all the chaos. For example, he might be tired of the constant battles against the Dark Arts and the politics within Hogwarts and the Ministry. He could stop caring about his reputation as 'the Chosen One' and simply want to live a quiet life, away from the spotlight and the expectations.
Maybe the Sorting Hat could be used on the Transformers. The Autobots are sorted into Gryffindor for their bravery and the Decepticons into Slytherin for their cunning. Then a battle ensues within Hogwarts between the two factions, with the wizards caught in the middle, trying to keep the peace and protect their school.
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 plot could be that Harry, having grown up without his parents, yearns for a mother figure. Maybe he starts to see a kind witch in the wizarding world as a mother - like substitute. She could teach him things his mother might have, like family spells or stories about his family's past.
One possible plot could be that in an alternate version of the Triwizard Tournament, Harry and Cedric form a closer bond during the tasks. They start to understand each other on a deeper level and as a result, share a kiss as a sign of mutual respect and new - found friendship. Maybe they work together to overcome a greater threat that wasn't in the original tournament, and this shared experience brings them closer.
One possible plot could be that Queenie discovers she is pregnant during a time of great unrest in the wizarding world. She might be worried about the future of her child, especially considering the ongoing threats. Maybe she and her partner (whoever that may be in the fanfic) have to go into hiding to protect the unborn baby from dark forces. They could be constantly on the move, seeking safe places within the wizarding community or even among the No - Majs (Muggles).
Well, perhaps in the fanfic, Voldemort has somehow found a way to cross over into Kim's world too. Harry, now adopted by Kim, has to protect both his new family and this new world. Kim and her friends are initially skeptical about Harry's magic but soon realize how useful it can be. They start training together, with Kim teaching Harry some of her combat moves and Harry showing her the basics of magic. This way, they combine their skills to face the threat of Voldemort and his new minions in this strange new world.