Maybe some of the old grudges between wizarding families that were thought to be resolved start to flare up again. This could lead to a lot of political intrigue within the wizarding community. And the children of the main characters could get caught up in this web of family feuds, having to decide whether to follow their family's old ways or try to make peace.
One possible storyline could be the children of the original characters starting their own adventures at Hogwarts. They might face new threats that are related to the past but in a different way. For example, a new dark wizard could be trying to revive the ideas of Voldemort and the kids have to stop it using the knowledge passed down from their parents.
One possible storyline could be that Harry leaves to explore the wizarding world outside of Britain. He might go on a journey to discover new magical creatures and spells in far - off lands. Another could be that he leaves to find a place of peace and solitude, perhaps in a hidden magical enclave, to deal with the trauma of the war. And he could also leave to train young wizards in secret, away from the public eye, to ensure they are well - prepared for any future threats.
Another storyline could involve the reactions of their friends. Hermione and Ron might be there to support Ginny throughout her pregnancy. There could be a lot of scenes of them sharing their experiences and knowledge about having a baby, adding a touch of friendship and camaraderie to the story.
One possible storyline could be them rebuilding the wizarding world together. They might focus on restoring Hogwarts, with Ginny using her Quidditch skills to start a new team there and Harry helping with the overall magical education revival. Harry could also be involved in Auror training reform, and Ginny would support him through it all, and they'd start a family in the newly peaceful wizarding world.
One possible storyline could be Harry struggling with PTSD from the war. He might isolate himself in Grimmauld Place, haunted by the memories of those he lost. Another could be him trying to find a new purpose in life, perhaps traveling the wizarding world alone to discover forgotten magic. Or he could be dealing with the public's perception of him as the 'Chosen One' and feeling the pressure to always be strong and heroic.
One possible storyline could be Harry's struggle with his newfound loneliness and how it affects his magic. He might start to isolate himself more from his friends at Hogwarts, fearing that he'll lose them too. Another could be Harry's determination to avenge Sirius by seeking out the Death Eaters responsible for his death more aggressively.
A possible storyline could be that a lost grimoire is found which contains spells using Belladonna. The finder, perhaps a young witch or wizard, has to figure out how to use it without getting poisoned by the Belladonna - related magic. This could lead to a series of trials and learning experiences as they navigate the dangerous and unknown magic.
Well, a storyline could involve Dumbledore kissing Harry as a way to seal a magical pact. This pact could be related to protecting Hogwarts or the wizarding world from a great threat. It might also be a situation where Dumbledore's actions are misinterpreted by others in the wizarding community, leading to a lot of drama and conflict. And in some fanfictions, it could be a moment of time - bending magic where Dumbledore from the past or future comes to Harry and the kiss has some profound significance for the timeline.
In some fanfictions, there could be a situation where Thanos is actually related to an ancient dark magic in the Harry Potter universe. Harry has to figure out this connection and use it to his advantage. Maybe Thanos is after a powerful magical artifact in the wizarding world that he believes will enhance the power of the Infinity Stones. Harry and his friends then have to protect this artifact while also trying to defeat Thanos, which could lead to a series of epic battles and magical duels.
Maybe Harry gets assigned to a special project at Gringotts. For example, to help relocate a very dangerous magical item from one vault to another. Along the way, he has to face various challenges like magical traps and other creatures that guard the vaults. This could lead to a series of adventures as he tries to complete the task.