Maybe in the fanfiction, there's a situation in a collapsing wizarding building. Fred is trapped under some rubble and Percy, using his skills and knowledge of magical architecture, manages to find a way to free Fred. As they escape, they start to realize how much they've missed having a proper relationship with each other, and Percy makes a vow to always be there for Fred.
A third plot could revolve around Percy's family relationships. He could be feeling overshadowed by his more popular siblings. So, he decides to prove himself in a different way. He enters a magical competition that tests not only magical skills but also strategic thinking. Along the way, he learns to appreciate his family more and they start to see him in a new light.
One idea could be Percy trying to understand the twins' pranks and finally joining in on one. Another could be the twins getting Percy to loosen up during a stressful time at Hogwarts, like exam week. Maybe they play a prank that backfires and Percy has to help them fix it without getting in trouble with the professors.
One idea could be Percy being sorted into Slytherin instead of Gryffindor and how that changes his relationships with his family. For example, he might have a more strained relationship with his Gryffindor siblings at first. Another plot could be Percy using his Slytherin cunning to outwit his political rivals in the Ministry of Magic later in life. Or perhaps a plot where Percy has to team up with some Slytherin students to solve a mystery that the Gryffindors are too head - strong to figure out.
Another plot could involve Percy being assigned to work with Hermione on a top - secret project at Hogwarts. Maybe it has something to do with protecting ancient magic texts. Along the way, they learn to respect each other's different approaches and form an unlikely friendship.
Maybe a fanfiction where Percy and his family get magically transported to a different era. They have to rely on each other and their family bonds to find a way back. Percy, being the rule - follower, might struggle at first with the lack of established rules in this new situation, but then he realizes the importance of his family's more flexible ways.
Perhaps there could be a time - travel plot where Hermione and Percy are sent back in time together. They have to rely on each other to get back to their own time. During this adventure, they see different sides of each other. Percy sees Hermione's quick thinking in a completely different context, and Hermione sees Percy's loyalty to his family and friends in a new light, which could lead to a romantic relationship.
One plot idea could be that Percy's twin sister is the opposite of him in terms of Hogwarts house. While Percy is in Gryffindor, she could be in Slytherin, causing a lot of family drama. Another idea is that she has a special magical talent that Percy is jealous of, like being able to communicate with magical creatures in a unique way. Or perhaps she gets involved in a secret society at Hogwarts that Percy disapproves of, leading to conflicts between them.
A plot could revolve around Percy being sent on a mission by the Order of the Phoenix that is similar to what the Scarlet Pimpernel did. He has to assume a false identity in the Muggle world while also dealing with his own insecurities and the expectations of his family back in the wizarding world. Along the way, he meets a Muggle girl who he falls in love with, but he has to keep his true identity a secret from her, adding a romantic sub - plot to the fanfiction.
A plot could involve Fred being affected by a spell that makes him slowly lose his memories. Hermione notices the signs early on and starts researching in the restricted section of the library. She finds a rare counter - spell that requires a great deal of magical power and precision. With the help of her friends, she manages to gather the necessary ingredients and perform the spell to save Fred's memories. Another idea is that Fred is in a situation where he's being influenced by a malevolent magical entity. Hermione detects it and uses her logical thinking and knowledge of magical defenses to exorcise the entity and save Fred.
One plot idea could be that Arthur discovers Ginny has a special magical talent that she's been hiding out of fear. He then helps her gain confidence in using it. For example, it could be a unique form of wandless magic. Another idea is that they go on a magical adventure together, like exploring an ancient, forgotten wizarding site. There, they encounter strange magical creatures and have to use their combined knowledge and skills to get out safely.