Another storyline could be that Harry leaves to help other wizarding communities that were affected by the war but didn't receive as much attention as the British one. He could use his skills and fame to bring resources and support to those areas. He might also start teaching magic to the younger generations in those places, passing on his knowledge and experiences.
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 that were previously unknown to him. Maybe he wants to find a place where he can truly be at peace after all the chaos of the war.
Perhaps Harry leaves because he feels a sense of isolation in the wizarding world he once knew. He might leave to find a new identity for himself, away from being 'The Boy Who Lived'. He could start a new life in a Muggle town, learning about Muggle ways and trying to blend in while still having his magical abilities, but keeping them a secret from the Muggles.
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.
In this fanfiction, Harry could be alone because he feels estranged from his friends who have moved on with their lives in different ways. So he takes on a solitary mission to protect the wizarding world in the shadows. He becomes a sort of unseen guardian, constantly thwarting small threats that could potentially grow into big problems, all while dealing with his own loneliness and the memories of the war.
One possible storyline could be them traveling the world together to help rebuild the nations. They could use Aang's Avatar powers and Katara's waterbending skills to bring water to drought - stricken areas or help with construction using earthbending - like techniques. Another could be them settling down in the Southern Water Tribe and starting a family while also teaching the next generation about the importance of the four nations' unity.
One possible storyline could be about the trio's efforts in rebuilding Hogwarts. They might use their magic to restore the damaged parts of the school, and also deal with the memories left behind by the war. For example, Neville could be helping them in the Herbology department, which was probably in a mess after the battle.
One possible storyline could be them rebuilding their lives in a post - war wizarding world. They might focus on raising their son, Teddy, and trying to create a normal family life despite the hardships they've faced. Another could be their involvement in the reconstruction of the wizarding society, using their experiences during the war to make positive changes.
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.
Perhaps Harry meets magical creatures that are rarely seen by wizards. Since he is out exploring after the war, he might stumble upon a group of centaurs who have their own unique wisdom about magic and the future. He could also encounter veelas, and through his interactions with them, learn more about the different cultures within the magical world. There's also a chance he meets other young wizards who are on their own adventures, and they form a sort of traveling group together.
One possible storyline could be Percy struggling with PTSD. He might have nightmares about the war and find it hard to reintegrate into normal life. For example, he could avoid social situations because the noise and crowds remind him of the chaos of the battlefield.
One idea could be the emergence of new villains or threats that are not directly related to the previous war. These could be dark forces that were awakened or created due to the chaos of the war. The heroes would then have to come together again, but this time in a different context, where they have to use their post - war experiences and new - found unity to face these threats.