Well, they could embark on a quest to find a powerful magical artifact that could help in the fight against Voldemort. Sirius would use his skills as an Animagus and his knowledge of the wizarding world's hidden corners, while Harry would contribute his own unique magic. Along the way, they would face various challenges, like dark wizards sent by Voldemort to stop them, and have to outwit magical creatures protecting the artifact. It would be a great adventure filled with danger and discovery.
One adventure could be that they try to find other allies. Sirius and Harry might travel to different wizarding communities, both in Britain and abroad, to gather support. They could meet interesting characters, some of whom might initially be suspicious of them but later become friends. This would involve a lot of interaction with different cultures in the wizarding world, learning new spells and magical techniques, and building a network of people who are against Voldemort's tyranny.
In France, Harry could end up at Beauxbatons Academy. There, he might participate in their unique magical competitions. He could also learn about different forms of divination or potions that are specific to the French curriculum. He might face some challenges with the language barrier at first, but as he delves deeper into the French wizarding community, he starts to pick up the magical French terms and use them to his advantage. He could also form a bond with a French witch or wizard who helps him navigate this new world.
The Weasley family could also be of great help. Molly Weasley, in particular, has a motherly instinct. She could take Harry in and help him with the pregnancy as if he were one of her own children. The Weasley twins might also be able to create some useful magical items for Harry to use during his time away, like special potions for a healthy pregnancy or charms to keep him hidden. And Ron, as Harry's best friend, would be there to support him emotionally and physically, even if he was initially shocked by the situation.
He could stumble upon a hidden wizarding community that has been cut off from the rest of the world for centuries. There, he might learn new magic spells and techniques that are unknown to the outside wizarding world.
They could have an adventure where they stumble upon a hidden magical creature sanctuary. They might need to help protect it from poachers or some other danger.
They might also embark on a diplomatic mission. With the wizarding world in a state of flux after the war, different magical communities need to be brought together. Harry, as a well - known figure, and Ginny, as a respected witch, could visit other wizarding countries to establish alliances and promote cultural exchange. This would involve meeting different magical customs, dealing with political intrigue, and making new friends and enemies along the way.
There's a fanfic titled 'Escape and Rediscovery'. Female Harry Potter runs away after feeling betrayed by some of her so - called friends at Hogwarts. She travels far and wide, learning different forms of magic from various sources. It has a really unique plot and great character development.
After running away, she could start a new life as an anonymous witch. She could use her skills to help Muggles in secret. She might use magic to heal the sick or prevent disasters in the Muggle world. This new life could give her a sense of purpose and also make her a more well - rounded witch as she learns about the Muggle way of life and how to integrate magic into it in a more discreet way.
He might meet American witches and wizards. Maybe a young and adventurous wizard who shows him around the American magical world.
Perhaps he'll meet a mysterious old wizard who lives in a secluded temple in the mountains. This wizard could be a master of ancient Japanese magic and could teach Harry about the spiritual side of magic that is deeply ingrained in Japanese culture. Harry might also meet a group of young Japanese witches who are training to become magical healers. They could share their knowledge of Japanese magical plants and how to use them for healing, which would be very different from the healing methods Harry learned at Hogwarts.
Perhaps he uses the island as a secret training ground. He could practice advanced spells away from the prying eyes of Hogwarts faculty and students. Harry might also build his own magical fortress on the island for protection and privacy.