A possible plotline could be that they start to investigate the true history of the Black family. As they dig deeper, they find out secrets that could change the course of the wizarding world. They might also use their status as Lords of the Black family to form new alliances. For example, they could reach out to other families that were previously at odds with the Blacks. This would not only strengthen their position but also help in the fight against the forces of evil. Along the way, they would have to deal with their own personal growth and how being part of the Black family affects their identities, especially Harry, who has always been an orphan with no real family until now.
Yes, there are quite a few. You can start by looking on popular fanfiction websites like Archive of Our Own. Some fanfictions in this theme might explore the implications of both Harry and Sirius having a connection to the Black family legacy, perhaps delving into how they deal with the family's dark past while also reclaiming its noble aspects.
Some fanfictions explore the idea of Sirius Black and Harry going on secret adventures together. Maybe they discover a hidden part of the wizarding world or try to solve an ancient mystery that has been long forgotten. This kind of plotline often involves a lot of action and exploration.
One interesting plotline could be a mystery - solving one. Harry discovers some strange artifacts in Grimmauld Place that were left by Regulus. With Sirius (if he's alive in the fic), they try to figure out what these artifacts mean and it leads them to uncover a long - forgotten plot by Voldemort. Another plotline could be a redemption arc for Regulus. Harry, after learning about Regulus's attempts to undermine Voldemort, tries to clear his name in the wizarding world, which causes some friction with those who still see the Black family as mostly dark wizards. And there could be a plotline about family secrets. Sirius and Harry find out that there are hidden magical abilities in the Black family bloodline that only Regulus knew about, and they have to figure out how to use or control them.
A common plotline is them teaming up to solve the mystery of Sirius Black's past. His daughter wants to know more about her father and Harry, having known Sirius, is also interested. They end up on an adventure filled with magic and danger.
A plotline might involve Sirius and Harry living together and Sirius trying to give Harry a normal family life. He could cook for Harry, help him with his homework, and they could have a pet together. Maybe they get a Kneazle, and Harry learns to take care of it with Sirius' guidance. This would be a contrast to the cold and often neglectful treatment he received from the Dursleys. And as Harry grows, Sirius could introduce him to his old friends like Remus Lupin in a more family - like setting, strengthening Harry's support system.
One possible plotline could be Harry learning more about his parents from Sirius. Sirius could share all the little details, like how James was in school, his mischievous deeds, and how he courted Lily. This would give Harry a deeper connection to his family's past. Another could be Harry and Sirius training together in magic, especially in defensive spells. Sirius, being a skilled wizard, could teach Harry some unique spells and techniques that he might not learn at Hogwarts. Also, they could have adventures in the wizarding world together, exploring places that are off - limits to most students.
One possible plotline could be that Sirius and Remus initially struggle with their inappropriate feelings towards Harry. They might then realize it's wrong and instead focus on their roles as his protectors. They could channel their strong emotions into teaching Harry more about his parents and the wizarding world, turning a potentially dark concept into a positive mentoring relationship.
One possible plotline could be that Sirius Black has been under some dark magic influence. Maybe a powerful dark wizard has managed to manipulate his mind, making him believe Harry Potter is a threat to him or the wizarding world in some false way. This could lead to a series of events where Harry tries to prove his innocence and figure out what's wrong with Sirius. Another could be that there's a misunderstanding based on some prophecy or false information spread within the wizarding community. Sirius, being impulsive, jumps to conclusions and decides to disown Harry without fully understanding the situation.
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.
Family secrets play a big role. There are likely to be hidden spells, treasures or dark pasts that Sirius uncovers as Lord Black. Also, his relationships with other characters change. His friends might view him differently now that he has this new status, and he has to navigate those changes.