One possible scenario in this fanfiction could be that a de - aged Tony Stark brings a new perspective to the events of Civil War. He might be less jaded and more idealistic, trying to find solutions that the older, more conflicted Stark couldn't see. Maybe he forms unexpected alliances with other characters based on his fresh outlook.
There's a fanfic called 'De - Aged Stark's New Adventures'. In this story, de - aged Tony forms an unlikely friendship with a young inventor. They work together on projects that could change the world. It's interesting to see how Tony's adult knowledge combines with a child's creativity in this one.
The 'family - like bond' trope is often seen. De - aged Tony forms closer bonds with the people around him, almost like a family. They protect him and he in turn, uses his genius to help them. For instance, he might become like a little brother figure to some characters. And there's also the 'coming - of - age' trope even though he's already an adult. He still has to grow in this new de - aged state, learning new things about himself and the world.
A possible plotline is that the de - aged Peter and Tony have to work together to solve a problem that only their combined knowledge, both from the present and Peter's future - self's knowledge, can fix. For example, they might need to stop a villain who has a time - related weapon that de - aged Peter in the first place. This would involve Peter using his spidey - sense in a different way as a kid and Tony using his tech skills to analyze the weapon and figure out how to reverse its effects not just on Peter but also on any other potential victims.
Pepper Potts could be a big help. She knows Tony so well, and she could try to jog his memory by showing him things from their past together, like pictures or mementos. Rhodey could also be there for him. He could tell Tony stories about their military days and how they became friends, which might trigger some memories.
One common character paired with him is Bruce Banner. They could be gaming buddies, with Bruce using his scientific knowledge to help Tony improve his games or vice versa. Another is Pepper Potts. She might be shown as someone who tries to get Tony to take a break from his intense gaming sessions.
The de - aged Tony could also form a mentor - mentee relationship with a younger Avenger. He has the knowledge and experience of his older self but the energy and fresh perspective of his de - aged self. This relationship could be a key factor in how the story progresses, as he imparts his wisdom in a different way and the younger Avenger helps him see things from a new angle, which could potentially change the course of the Civil War in the fanfiction.
At first, Tony might be skeptical about the whole situation. But as he sees the de - aged Peter's potential and his spidey - sense in action, he starts to warm up. They could develop a relationship where Tony is constantly protecting Peter from both physical threats and the knowledge of the future that Peter might accidentally reveal. Peter, on the other hand, would be in awe of Tony's intelligence and resources and would try to learn as much as he could from him. Their relationship would be a mix of mentorship, friendship, and a bit of a father - son dynamic.