Maybe her secret father is a key to unlocking a great power within Hermione. The discovery of her father could lead to her having new and unexpected magical abilities. For example, if her father was part of an ancient magical bloodline, Hermione could inherit abilities from that line that she never knew she had. This could change the way she interacts with the wizarding world and her friends, as she tries to understand and control these new powers.
A possible plot twist is that her secret father was thought to be dead but is actually alive. His return could cause chaos in Hermione's life as she has to deal with the truth about her family, and also face the consequences of his actions in the past. It could also lead to a conflict between her loyalty to her adoptive parents (if she has any in the fanfic) and her new - found connection to her real father.
One plot twist could be that her secret father is actually an enemy in disguise. He might have some evil plan that involves Hermione unknowingly.
It could be a powerful wizard who has been in hiding all this time. Maybe someone with a dark past that the author wants to explore.
One possible plot twist could be that Hermione's pureblood status was hidden to protect her from a dark wizard or an old family feud. When the truth comes out, she has to face unexpected enemies.
One possible plot twist could be that the Dursleys are actually under a spell that makes them act so horribly, and Hermione discovers and breaks it. Another could be that Hermione finds out she has some family connection to the Dursleys, which would be a huge shock for everyone.
A possible plot twist could be that the wife is not who she seems. Maybe she has a hidden identity or a past that she has been hiding from the husband as well. And when the truth about her starts to surface, it throws the whole secret relationship into chaos. For example, she could be related to someone who is an enemy of the husband's family or business, and this revelation would put both of them in a very difficult situation.
One possible plot twist could be that the revelation of Izuku being All Might's son makes him a target. Villains might see him as a valuable hostage or a way to get back at All Might. Another twist could be that there are some hidden powers or abilities that Izuku inherits from All Might that were previously unknown. This could change the way he fights and his role in the hero world.
One possible plot twist could be that the baby has some unique magical abilities that neither Severus nor Hermione expected. Maybe the baby can communicate with magical creatures in a way no one has seen before. This could lead to all kinds of adventures as they try to understand and control this new ability.
One possible plot twist could be that the troll is actually under the control of a dark wizard. So when Harry saves Hermione, they realize that there is a much bigger threat at hand. Another twist could be that the troll turns out to be a transformed Hogwarts student, and they have to find a way to reverse the spell instead of just fighting it.
Maybe Hermione discovers that one of the Death Eaters training her has a change of heart. This Death Eater then starts to help Hermione escape or undermine the other Death Eaters from within the group. It adds an interesting layer of complexity to the story.
One possible plot twist could be that the kidnappers were actually working for a powerful dark wizard who wanted to use Hermione's intelligence for his own evil plans. Maybe they planned to brainwash her into becoming a powerful weapon against the wizarding world. Another twist could be that Hermione's real family had a dark secret and the kidnapping was an attempt to keep her away from it. For example, her family might have been involved in some sort of ancient dark magic that they didn't want her to discover. Or perhaps the kidnappers thought they were rescuing her from a prophecy that would bring doom to her if she stayed with her birth family.
The plot could take a turn where Zabini is initially seen as the bad guy because of the kidnapping, but in reality, he is trying to protect Hermione from a greater threat. Maybe there's a prophecy that involves Hermione and Zabini, and the kidnappers are trying to stop the prophecy from coming true. Another possible twist is that Hermione's kidnapping leads to a discovery of a long - lost magic that Zabini's family has been searching for. This magic could change the balance of power in the wizarding world, and now Hermione is in the middle of it all.