Yes, there are likely fanfictions out there with such a concept. Fanfiction writers often come up with creative and unexpected relationships between characters. They might explore how Tony Stark and Loki could be brothers, delving into their different personalities and powers, and how this new family dynamic would change the existing storylines in the Marvel universe.
There is definitely some out there. In some 'Tony Stark has a brother' fanfictions, the brother could be a rival, competing with Tony for their father's attention or for control of the company. Others might show them as a great team, using their combined genius to save the world in ways that the Avengers alone couldn't.
There could be. Since fanfiction writers love to create unique and unexpected crossovers, the idea of Harry Potter being the brother of Tony Stark is an interesting concept that might have been explored. However, it's not a very common or mainstream crossover, so it might take some digging to find. You could also check some specialized fanfiction communities or forums where people might discuss or share such works.
One common theme is family reconciliation. Since Tony had a complex relationship with his father, having a brother can add another layer to that family dynamic. They might start off at odds but then come to understand and support each other.
Perhaps the plot could start with their unusual upbringing. Harry grows up with the Dursleys while Tony has his own issues with his father. They both develop their unique skills. When they meet, they realize they are brothers. They then start to combine magic and technology. For example, they could use magic to enhance Tony's suits or use technology to create new magical artifacts. Along the way, they face challenges from those who oppose the mixing of these two very different worlds, like some traditional wizards who don't trust technology and some tech - moguls who fear magic.
Maybe the plot could be about Tony and Howard competing to create the most advanced technology. They both want to prove themselves as the better inventor in the Stark family. Along the way, they encounter various challenges and enemies who are after their technology. But through it all, they learn to rely on each other and their brotherly bond grows stronger. This could also involve some cameos from other Marvel characters who are either helping or hindering their progress.
Well, it could be a fanfiction that delves into the emotional side of their brotherhood, showing how their bond influences their decisions and actions. Or perhaps it's a story with a twist, where their relationship leads to unexpected consequences and challenges within the Marvel world.
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.