Well, it could be that Percy has a hard time adjusting to the wizarding world at first. But then he meets a mentor figure who helps him understand his place in Hogwarts and he starts to thrive. He might even join the Quidditch team and become a star player.
In the 'Percy goes to Hogwarts fanfic', perhaps Percy is a transfer student. He quickly becomes involved in a mystery that dates back to the founding of Hogwarts. Along the way, he has to use his wits and newfound magic skills to solve the mystery. He also forms deep bonds with his housemates as they all work together to uncover the truth.
In this fanfic, Ciel could potentially be sorted into a Hogwarts house, say Slytherin because of his cunning nature. Then he would have to navigate the politics within the house while also exploring the secrets of the castle. He could also get involved in some kind of mystery that threatens Hogwarts and use his unique skills to help solve it.
Well, it could be about Naruto arriving at Hogwarts and being confused by all the magic there. Maybe he tries to use his ninja skills in a world full of wizards and witches.
In such a fanfiction, perhaps Percy was betrayed by his family or friends in the Ministry. When he goes to Hogwarts, he might find solace in the old castle. He could reconnect with his siblings in a more understanding way, and learn new magic that helps him in his quest for revenge or self - discovery. He may also team up with some unexpected allies among the students and teachers.
It could be a dark wizard who has infiltrated Hogwarts under a disguise. Percy might be the one to first suspect this wizard's true identity.
One possibility could be that Harry discovers he has some other magical destiny outside of Hogwarts. Maybe he is taken in by a different group of wizards who teach him their own brand of magic in a hidden location. They might believe Hogwarts is too mainstream or that Harry has a special power that needs to be nurtured away from the school.
Maybe Percy teaches Potions. He could start off by strictly following the textbook but then discovers a new potion ingredient while exploring the Hogwarts grounds. This discovery could lead to a whole new line of potions research in the fanfic. He would then involve the students in this exciting discovery, making potions class much more interesting than it was before.
In the 'sakura goes to hogwarts fanfiction', it could be that Sakura is a transfer student. She would face the challenges of adapting to the different magical system in Hogwarts. For example, she has to learn about potions and spells in the Hogwarts way. Along the way, she might discover a hidden mystery in Hogwarts that only she, with her special background, can solve. Maybe it has something to do with an ancient artifact that links her world to Hogwarts.
Well, it could be about Mal, who might be a new student at Hogwarts. Maybe Mal discovers a hidden magic ability that no one else has. He could make new friends and together they face some sort of mystery in the castle, like a secret room that holds an ancient magic that's in danger of being misused.
One possible plot could be Harry dealing with the trauma of living with the Dursleys. He might be constantly bullied by Dudley and neglected by the adults. In therapy, he could start to open up about his feelings of isolation and fear. Maybe he discovers his magic during these therapy sessions as a way to cope, like making small objects move when he gets extremely emotional. This would be a new take on his pre - Hogwarts life, exploring his psychological state rather than just the physical abuse he endures.
In a fanfic where Percy goes to Hogwarts alone, he could form some interesting friendships. He might befriend Neville, who is also a bit of an underdog. Percy could teach Neville some of his own courage -building techniques. And he would surely be a star in the Quidditch field with his athletic abilities, even if he has to learn the rules first.