A really cool plotline might be Sirius helping Harry deal with his fame. Sirius, having been through some of the wizarding world's spotlight himself, could give Harry advice on how to handle the media attention. He could also protect Harry from those who might want to use his fame for their own gain.
Another plotline could involve Sirius and Harry traveling together during the summers. They could explore different magical places, like hidden wizarding villages. This would strengthen their bond and also expose Harry to more of the magical world's secrets.
One interesting plotline could be Sirius teaching Harry advanced magic in secret. For example, Sirius might show Harry how to perform Patronus charms earlier than he does in the original story. This would give Harry an edge in dealing with Dementors and other dark creatures.
One possible plotline could be Harry learning all the unique Weasley family traditions. For example, he might participate in the annual Weasley family Quidditch match and discover new strategies from the Weasleys. Another could be his relationships with each Weasley sibling growing in different ways. He could have a really close bond with Ron as they grow up together, and also form special friendships with Ginny, Fred, and George. Maybe he gets to help Molly Weasley in the kitchen and learns some secret family recipes too.
One interesting plotline could be their adventures at Hogwarts together. They might study for exams in the library, and Harry could discover new spells with Daphne's help. Another could be them facing challenges like the Triwizard Tournament side by side.
One possible plotline could be Harry making new and unexpected friendships. For example, he might befriend a shy Hufflepuff student who has a hidden talent for magic that helps Harry in some way. Another could be Harry exploring parts of Hogwarts that are usually off - limits, like a long - forgotten attic filled with old magical artifacts.
In this type of fanfiction, a common plotline is Harry dealing with the after - effects of the war. He might have PTSD and have to learn how to cope with it while also trying to move forward in his life. His growth as a person could also involve him mentoring younger wizards, passing on his knowledge and experiences. And perhaps there are stories where he delves deeper into the history of magic, uncovering secrets that were previously unknown.
One possible plotline could be Harry learning magic from James at an early age, getting a head start on his Hogwarts education. Maybe they go on secret little adventures together in the wizarding world around their home.
One possible plotline could be Harry making friends with the hospital staff and other patients. They become like a second family to him, and he learns about different kinds of people from various backgrounds. Another could be Harry discovering his magical abilities while in the hospital, perhaps through some strange events that occur only he can notice, like objects moving on their own. Or maybe he uses his time in the hospital to study magic secretly, getting books sent to him somehow and practicing spells in his room when no one is looking.
One possible plotline could be Percy's struggle to adapt to the Hunt's way of life. He might have to learn their combat styles and rules. Another could be his relationships with the members of the Hunt, forming deep friendships or facing rivalries.
Well, perhaps he could discover new magical abilities related to orgpange. Maybe he'd use these unique powers to fight against the dark forces in a different way than in the original story.
One common plotline is Sirius Black escaping from Azkaban earlier and secretly training Harry in advanced magic. Another could be Sirius and Harry going on a hidden adventure to uncover more about Harry's parents. There are also stories where Sirius plays a more active role in the fight against Voldemort at Hogwarts, using his knowledge of the Dark Arts and his Animagus form to their advantage.
One common plotline could be Sirius teaching Harry more about his family's history in a way Dumbledore didn't. For example, Sirius might share hidden secrets about the Potter family magic that Harry was never aware of.