She could be sent to Forks as part of a cultural exchange program between the wizarding world and the world of Twilight. Once there, she has to adapt to the new environment while also dealing with the fact that she's a magic - user in a place full of vampires and werewolves. She might start a school for magic in Forks, teaching the locals some basic spells and in turn, learning about their way of life.
A plot could revolve around a prophecy that involves both the wizarding world and Asgard. Harry is the key figure in the prophecy. He travels to Asgard to find out more. There, he meets Odin who initially distrusts him. But as Harry proves his worth through his magical abilities and courage, Odin decides to help him. Together, they must face a common enemy that is emerging due to a dark magic that is seeping between the two worlds. Harry could also form a friendship with Sif, who teaches him some Asgardian fighting techniques.
Maybe Harry Potter arrives in Wakanda after a failed attempt on his life in the wizarding world. The Wakandans see his magical abilities and believe he is sent by their gods. They make him king. He then uses his knowledge of potions to create new substances that can enhance the properties of Vibranium. But there are some within Wakanda who oppose him, thinking he will bring chaos with his foreign magic, and he has to win them over.
It would probably be a wild mix. The female Harry Potter would be this outsider with amazing powers in Forks. She might befriend some of the locals, like Jessica or Angela. And when it comes to the vampires and werewolves, she could either be a threat or an ally. For example, she could use her magic to create some sort of protection spell around Forks to keep the vampires and werewolves in check.
One plot idea could be that a powerful dark magic causes a rift in time and space, bringing Harry and Lyanna together. They initially clash due to their different backgrounds but gradually fall in love as they fight against the dark magic that brought them together. Another idea is that Harry, while exploring some ancient magic in Hogwarts, accidentally travels to Westeros and meets Lyanna. They bond over their shared sense of justice and adventure, and their marriage unites the magical world of Harry with the political world of Lyanna's family.
There are quite a few out there. Some fanfictions explore how the female Harry Potter's magical abilities interact with the rather ordinary, yet mysterious world of Forks. For example, in a fic named 'Magic Meets Twilight Town', she has to hide her magic while also dealing with the local mysteries and new relationships, just like Bella in the Twilight series but with a Potter - like twist.
There are several places you can look for such fanfics. Archive of Our Own (AO3) is a great resource. Just type in the relevant keywords like 'female Harry Potter moves to Forks' in the search bar, and it will show you a list of available fanfics. Some fanfic communities on Reddit might also be helpful. You can post a request there and see if other fans can recommend some good ones.
One idea could be a story where a mistress is a strict but kind teacher at Hogwarts. She could be in charge of a special class that focuses on ancient magic spells, and the story could follow Harry and his friends as they struggle and learn in her class. Another idea is a mistress who is the caretaker of an old wizarding manor. Harry and his friends visit the manor for a school project and discover all kinds of magical secrets under her guidance.
One possible plot could be that Harry Potter moves to Forks because he's on the run from some dark magic threat in the wizarding world. In Forks, he meets the Cullens and they initially think he's just a normal human. But as time goes on, they notice his odd behavior. Harry, on the other hand, is fascinated by their vampiric abilities and starts to wonder if there are similarities between vampires and some of the magical creatures he's encountered in his world. They could end up teaming up to face a common enemy that threatens both the wizarding world and Forks.
One plot idea could be Harry going back to the time when Voldemort was still at Hogwarts as Tom Riddle. He could try to prevent Riddle from turning into Voldemort by befriending him and showing him a different path. Another idea is that Harry goes back to the time of the founders of Hogwarts. He might learn ancient magic directly from them and use that knowledge to change the future of the wizarding world. Also, he could go back to a time when his parents were alive and get to know them better, which would be a very emotional journey for him.
One plot idea could be that there is a portal that accidentally opens between the wizarding world and the ninja world. Harry and Naruto meet through this portal. They initially have misunderstandings due to their different ways of life but gradually fall in love. As they get married, they have to deal with political issues in both worlds. Some in the wizarding world might fear Naruto's power and some in the ninja world might be suspicious of Harry's magic.