It would be amazing. Just imagine Iron Man's high - tech suit in the Star Wars universe. He could be a lone bounty hunter with his advanced weaponry, or perhaps he teams up with the Rebels and uses his technology to upgrade their ships. His suit's repulsors would be a new and powerful addition to the Star Wars combat scenarios.
One idea could be having Iron Man's technology integrated into the Star Wars universe. For example, imagine Iron Man's suit being used by a Rebel pilot. It could give them an edge in dogfights against the TIE fighters. Another could be Tony Stark somehow getting stranded in the Star Wars galaxy and using his wits and tech to survive. He might start building new gadgets using local resources and his knowledge from Earth.
The 'unlikely alliance' trope is also common. For example, Iron Man teaming up with Darth Vader before Vader's full turn to the dark side. They might work together on a project that could change the fate of the galaxy. And then there's the 'culture clash' trope, with Stark's modern Earth values clashing with the values in the Star Wars universe.
In fanfiction, Iron Man could fit into the Star Wars universe in many ways. One way is that he could be a time - traveler of sorts. He arrives in the Star Wars era and decides to use his technology to make a name for himself. He could start his own faction, using his Iron Man suits as his army. His suits could be modified to blend in with the Star Wars aesthetic. He'd have to learn about the Force and how it affects the balance of power, and his relationships with the various species and characters would be a major part of the story.
One interesting crossover could be Iron Man's technology being introduced into the Star Wars universe. Maybe he could help upgrade the droids or the starships with his advanced engineering skills. Another could be a scenario where Tony Stark finds himself in the middle of a lightsaber duel, using his suit's capabilities to fend off the Jedi or Sith.
Another popular character is Chewbacca. Picture Chewbacca and Iron Man in the same scene. Iron Man might be initially confused by this large, furry alien, but then they could end up working together. Maybe Chewbacca helps Iron Man understand some of the more wild aspects of the Star Wars universe while Iron Man uses his tech to solve problems for Chewbacca's friends.
There are some fanfictions that focus on a team - up between Iron Man and a Star Wars character like Han Solo. Imagine them going on a smuggling adventure together, with Iron Man's high - tech gadgets and Han Solo's piloting skills. It would be an exciting read. Also, there could be a story where Iron Man helps the Rebel Alliance with his advanced weaponry and strategic mind.
One way to make it unique is through the plot device. Suppose there is a device that can swap the powers of the characters. So Spider - Man gets the lightsaber skills and some Jedi powers, while a Jedi like Obi - Wan Kenobi gets spider - like abilities. This would completely change how they interact with their respective universes and enemies. Also, the tone of the fanfiction could be different. Instead of the typical action - adventure, it could be a more comical take on the crossover, with Spider - Man constantly making jokes about the Star Wars technology and the Star Wars characters being baffled by his New York lingo.
One possible plot for a Deku Iron Man fanfiction could involve a threat that neither hero can face alone. The villains could be creating a device that combines the technology of the Marvel universe with the quirks of the My Hero Academia world. Deku and Iron Man would have to team up, using their respective skills and powers. Deku's agility and experience with his quirk, combined with Iron Man's high - tech weaponry, would make for a great story.
One idea could be that Iron Man's technology somehow ends up in the RWBY universe. Maybe Tony Stark himself gets transported there. He could then use his tech to upgrade the weapons of the RWBY characters. For example, he might enhance Ruby's scythe with some of his repulsor technology, making it even more powerful in combat.