Well, one possible plot could be the daughter trying to prove herself to Tony despite his initial rejection. Maybe she has some amazing scientific skills that she uses to solve a big problem, and in the process, she starts to earn his respect.
Another plot might involve the daughter getting involved in a battle or conflict that Tony is also a part of. She could be on the side of the good guys but still be at odds with her father. She might have to save him at some point, which could start to change their relationship.
One interesting plot could be the daughter suddenly showing up at Stark Tower. She might have grown up in secret, perhaps because her mother wanted to protect her from the dangerous world that Tony Stark is often involved in. She then has to navigate her newfound relationship with her father and all the high - tech and superhero craziness that comes with it.
Pepper Potts could be a common character. She might be in a position where she tries to mediate between Tony and his unwanted daughter, either trying to get Tony to be more accepting or helping the daughter understand Tony's perspective.
One possible plot could be Tony Stark, as a female, facing the same challenges in the tech world but with added sexism to overcome. She might have to prove herself even more than her male counterpart did. Another could be a female Tony Stark in a romantic relationship with a different character, like Thor, and how that changes the dynamics of the Avengers. Also, she could use her femininity in unique ways to solve problems, for example, using charm and guile where the male Tony might have used brute force or pure intellect.
One plot could be that a powerful enemy kidnaps Tony Stark to steal his Iron Man technology. They hold him in a secret lair and try to force him to reveal all the secrets of his suits. Another could be a fan with an extreme obsession who kidnaps him, thinking they can make him see things their way. Maybe they want him to create a special weapon just for them.
There could be a fanfiction where Tony Stark's daughter has to deal with the pressure of living up to her father's legacy. In this story, she might struggle with school and friendships because everyone expects her to be as brilliant as her dad. But in the end, she finds her own path and uses her intelligence in a different but equally amazing way.
One interesting plotline could be her inheriting Stark Industries and facing the challenges of living up to her father's legacy. She might have to deal with rival companies trying to take over while also trying to innovate in her own way.
Another plotline could involve the daughter dealing with the legacy of being Tony Stark's child. She could face pressure from the public and other superheroes, while also trying to carve out her own identity. She might struggle with living up to her father's reputation or trying to break free from it.
Another plot could be that in a post - apocalyptic world that combines elements of both universes, Harry and Tony are the last hopes for survival. Harry uses his magic to fend off dark magical creatures, while Tony uses his tech to combat advanced technological threats. They must learn to trust each other completely to save both the wizarding and non - wizarding parts of this new world.
One interesting plot could be the challenges they face in a world that is not used to male pregnancy. They might have to deal with public reactions, both positive and negative. Another plot could be how they support each other through the physical and emotional changes that come with pregnancy.
One interesting plotline could be the adopted daughter developing her own unique suit under Tony Stark's guidance. It shows her growth and the bond between them as she learns from the genius.