Well, a cool plot might involve Iron Man being accidentally transported to the Transformers' home planet. There, he has to use his wits and his suit's capabilities to survive. He could end up forming an alliance with some of the Transformers, like Optimus Prime, and they come up with a plan to get him back to Earth while also dealing with a threat to both their worlds. This would involve a lot of cool tech - sharing and strategic planning between the two very different kinds of heroes.
One idea could be a scenario where the Autobots from Transformers Prime team up with Iron Man to fight a common enemy like an evil tech - based villain. They could combine their technological prowess. For example, Iron Man could share his advanced weaponry designs with the Autobots, and in return, the Autobots could teach Iron Man about their energy sources.
One interesting idea could be a crossover between Transformers and the Harry Potter universe. Imagine Optimus Prime leading the Autobots through Hogwarts, facing magical threats alongside the wizards. Another could be a Transformers and Star Wars crossover, with the Autobots and Decepticons getting involved in the Galactic Civil War. Maybe the Transformers' advanced technology could have an impact on the balance of power in the Star Wars galaxy.
One idea could be that Iron Man's technology somehow gets integrated into the world of RWBY. Maybe his suits' energy systems could be used to power up the Huntsmen and Huntresses' weapons. For example, Ruby could have a Crescent Rose upgrade with Iron Man's repulsor technology, allowing for more powerful ranged attacks.
A really cool plot could be a parahuman in the Worm universe who idolizes Iron Man and tries to recreate his suits using their powers. They face challenges as the technology and powers don't always mesh well, but through trial and error, they manage to create a unique hybrid of Iron Man - like tech and their own parahuman abilities.
One idea could be having the Autobots and Decepticons end up in the Bayverse's version of Chicago during a major crisis. They could team up with the local military forces there to fight a common enemy, like an alien invasion that is different from their own Cybertronian battles. Another idea is to have a human character from the Bayverse accidentally stumble upon a hidden Cybertronian relic that has the power to transform Earth's technology in unexpected ways, leading to a race between the Transformers and various human factions to control it.
One idea could be a crossover with the Autobots from Transformers Prime and the Titans from Attack on Titan. Imagine the Autobots having to fight the Titans in a post - apocalyptic world. Another idea is a crossover with the Power Rangers. The Rangers and the Autobots could team up to fight a common enemy that threatens both their worlds. A third idea might be a crossover with the Teenage Mutant Ninja Turtles. The Turtles could use their ninja skills along with the Autobots' firepower to take on a new threat in New York City.
A cool plot could be that a villain in the Boku no hero world steals Iron Man's technology and starts creating chaos. The heroes then have to figure out how to stop the villain while also dealing with the unfamiliar technology. Or perhaps a young inventor in the Boku no hero world idolizes Iron Man and tries to recreate his suits, but with a twist related to quirks. This could lead to a story about the young inventor's journey, from being an unknown to becoming a key figure in fighting crime with their unique Iron Man - inspired creations.
I think Iron Man and Bumblebee would be really interesting. Bumblebee is a fan - favorite Transformer, and his more light - hearted personality could contrast well with Iron Man's often - cocky demeanor. They could have some fun banter while also working together to solve problems. Also, Iron Man could help repair Bumblebee if he gets damaged, and Bumblebee could show Iron Man some cool Transformer - only maneuvers.
Perhaps there is a portal that connects Cybertron and Equestria. Some ponies accidentally end up on Cybertron and are shocked by the mechanical world. The Transformers have to help them get back home. Meanwhile, some Autobots are curious about the ponies' world and decide to accompany them. This leads to a cultural exchange of sorts between the two groups, with lots of misunderstandings at first but then growing respect and friendship.
One idea could be to explore his origin story in more depth. Maybe he has a hidden family or a past trauma that shaped him into the man of iron. Another could be to put him in a different time period, like the future where technology has advanced even more and he has to adapt.