What are some interesting plotlines in 'Harry has a sister' WBWL (What if Voldemort had won) fanfiction?

In many WBWL fanfictions where Harry is powerful, he often uses his hidden powers to resist Voldemort's regime. For example, he might have an extraordinary control over magic that was suppressed in the original story. He could use this power to secretly help the resistance, like teaching other wizards and witches how to fight against the dark arts in new and unexpected ways.

One great 'Cold Harry Potter WBWL' fanfiction is 'The Boy Who Lived Again'. It shows a darker and more complex wizarding world under Voldemort's rule. Harry has to hide his true identity and find a way to fight back.

One possible scenario could be that the entire wizarding world falls into complete chaos. With Harry gone, there's no one to oppose Voldemort directly. The Death Eaters might take over Hogwarts and turn it into a dark academy, teaching dark magic and suppressing any form of resistance. The Order of the Phoenix would be in disarray, losing their main hope.

One interesting plotline could be Snape realizing that Harry is not like the 'Boy Who Lived' (WBWL) as everyone expected. Maybe Harry has a different approach to magic that Snape initially scoffs at but later comes to respect. For example, Harry might be more interested in the darker arts in a way that challenges Snape's views.

One popular fem Harry WBWL fanfiction is 'The Girl Who Lived'. It has an interesting take on how a female Harry would navigate a world dominated by Voldemort. Another is 'Fem Harry's New Path' which explores her character development in this dark alternate reality. There's also 'A Fem Harry's Struggle' which delves into the challenges she faces as she tries to resist the new regime.

One popular 'Harry Potter and Tonks WBWL' fanfiction is 'The Darkened World'. In this story, Tonks has to fight against the new oppressive regime secretly. It shows a very different Hogwarts, full of dark magic influence. Another great one could be 'Surviving in the Shadows' where Tonks uses her Metamorphmagus abilities in unique ways to resist the dark forces.

One interesting plotline could be the little sister discovering she has her own unique magical abilities that are different from Harry's. For example, she might be able to communicate with magical creatures in a way no one else can.

In this fanfiction concept, the plot could involve Harry being disowned and then being found by Death Eaters at a young age. They could try to indoctrinate him into Voldemort's ways. However, Harry's inner goodness resists. He could start a journey of self - discovery where he realizes that his parents' disownment was a part of a larger plan to keep him away from Voldemort's immediate attention. Along the way, he might find allies who knew his parents and help him understand the truth.

One interesting plotline could be that Harry discovers a new, powerful magic that gives him an edge in the fight against Voldemort. For example, he might find a way to combine different spells in an unexpected way. Another could be that Voldemort has a secret weakness that Harry uncovers through his friendships. Maybe one of his friends has a unique connection to an ancient magic that can be used against Voldemort.

One possible plotline could be that the children possess unique magical abilities due to their mixed heritage. For example, they might have the power to control both light and dark magic in a balanced way. Another could be that they are caught in the middle of the two worlds, with the wizarding community being suspicious of them because of their Voldemort connection, while Voldemort's remaining followers might try to use them for their own dark purposes.