A possible plot is that Bellatrix is sent back to the time when the Goblin Rebellions were happening. She could side with the goblins to gain their trust and then double - cross them to steal their most precious treasures. Another idea is that she is sent back to the time when the Ministry of Magic was first established. Bellatrix might try to infiltrate it from the start and plant the seeds of dark magic within its very foundation. Also, she could be sent back to a time when a famous magical beast was first discovered, and she tries to capture and control it for her own evil purposes.
Some fanfics explore Bellatrix's family relationships more deeply. Like her relationship with Narcissa. There could be a plot where Bellatrix has to choose between loyalty to Voldemort and protecting her sister, which adds a lot of emotional depth.
One idea could be exploring how Bellatrix's pregnancy affects her loyalty to Voldemort. Maybe she starts to question some of his more extreme actions as she thinks about the future for her unborn child.
A possible plot is that Anakin is sent back in time and ends up meeting his mother again when she was younger. This encounter could give him a chance to save her from the Tusken Raiders, which might then have a profound impact on his emotional state and his path in the Force. He could also use this opportunity to train himself differently, perhaps learning from the Jedi of that era in a more positive way, without the strictures that later led to his disillusionment.
Bellatrix's personality could be softened in some ways. Going back in time, she might see things differently. For example, if she goes back to a time when the wizarding world was more peaceful, she could start to question her loyalty to Voldemort. However, she could also become more desperate. If she realizes that she has a chance to change things for the worse in the wizarding world, she might be more eager to carry out her dark plans, and her already - extreme personality could become even more so.
One idea could be that Percy goes back to the time when the gods first came to power. He could try to change the way the gods interact with demigods from the start, leading to a whole new world order for demigods. Maybe he'd teach the early demigods some of the skills he has, like advanced sword fighting techniques.
One interesting plot idea could be Percy going back in time to the era of the Greek heroes. He could meet Hercules and learn from him. Maybe he would have to face the same challenges Hercules did, but with his own modern - day skills and knowledge. Another idea is that he goes back to the time when the gods first emerged and gets involved in the power struggles among them. This could change the entire course of mythology as we know it.
A major plot twist could be that the father of the child is a secret enemy spy. This would add a whole new layer of drama as Bellatrix's daughter has to deal with the betrayal and also protect her child from both sides. Another could be that the pregnancy is part of a magical prophecy that she was unaware of, and it has far - reaching consequences for the wizarding world.
A plot could focus on the relationship between Bellatrix and the father of the child. If it's a fellow Death Eater, how does their dynamic change? Do they become more protective of each other? Or perhaps the father is an unexpected character, like a wizard who was undercover among the Death Eaters. This would add a whole new layer of mystery and drama to the fanfiction.
One interesting fanfiction could be about Bellatrix's early years at Hogwarts. It might explore her friendship or rivalry with other Slytherins. Another could be a story where Bellatrix has a change of heart after a magical encounter and tries to redeem herself. And there could also be a fanfic that focuses on her relationship with Voldemort in a more in - depth way, showing the power dynamics and her unwavering loyalty.
One interesting fanfiction could be about Bellatrix's early years at Hogwarts and her first encounter with a young Harry Potter in a magically altered scenario. It might explore how their paths could have crossed in a different way than in the original books.