Maybe she'll come across an old enemy who has a different role or alignment in this new world. For instance, someone who was once her foe might be a potential ally in the opposite world.
She could meet her doppelganger. In the opposite world, it's possible that there is a version of herself with different characteristics or a completely different personality.
In the past, Sakura could meet the original creators of the magic system she uses. They might be able to teach her things that have been lost over time. She may also encounter a young, talented artist or inventor who was never mentioned in the history books. This person could be creating something that will have a big impact in the future. And there's always the possibility that she meets a kind - hearted stranger who becomes her best friend in the past and has a lasting impact on her life, even when she returns to her own time.
She might encounter strange creatures. In the opposite world, there could be magical beings that are completely different from what she has known in her own world. For example, there could be talking animals with special powers.
She could meet her future self. This would be an interesting encounter as they could compare their experiences and knowledge. Her future self might give her some advice on things she should do or avoid in her own time. Another person she could meet is a descendant of her friends. For example, a grandchild of Harry and Ginny who has inherited their bravery and magical skills.
Sakura would be the central character. In addition, there could be a young and brave local in the opposite world who becomes Sakura's guide. There might also be some shadowy figures that are controlling the chaos in the opposite world and Sakura has to face them to set things right. These characters would all interact with Sakura and shape the story as she tries to navigate this new and unfamiliar place.
Well, it could be about Sakura facing all kinds of strange and magical creatures in the opposite world. Maybe she has to find a way to get back home while dealing with new powers she discovers there.
There's a chance she could encounter her past enemies in a different context. Maybe she could find a way to befriend them or at least understand them better before they became foes. This could lead to preventing future conflicts. For example, if there was a villain who turned bad because of a misunderstanding, Sakura could clear it up in the past.
She could meet the founders of Hogwarts. Imagine Hermione having a conversation with Rowena Ravenclaw about the importance of knowledge and wisdom. She might also meet Godric Gryffindor and learn about the true meaning of courage from him. Another person she could meet is Salazar Slytherin. It would be very interesting to see how she would interact with him, given his views on blood purity.
She could meet soldiers coming back from World War I. These soldiers would have their own stories of war and survival, and Bella might be drawn into their tales.
He could meet his future self. This encounter might be full of surprises as his future self could have different views and experiences. His future self might be more jaded or more powerful.
He could meet an AU version of Hinata who is more assertive and outgoing. Maybe she's a powerful ninja in her own right and not as shy as in the original story.