A crossover with a post - apocalyptic world. Maybe after some catastrophic event, the robots from 'I, Robot' are trying to rebuild society in a world full of chaos and danger. They could team up with human survivors who are initially distrustful of them but gradually learn to rely on their abilities.
A crossover with a space exploration story. The advanced technology of the 'I, Robot' universe could be used in a space mission. The robots could be sent to explore a new planet, but they encounter strange alien technology that they need to figure out how to interact with, while also dealing with any malfunctions or ethical dilemmas that arise.
One idea could be a crossover with a detective story. The robots in 'I, Robot' could assist a detective in solving a complex crime that involves both human and robotic elements. For example, a robot might have witnessed a murder but its programming restricts it from fully disclosing what it saw. The detective has to figure out how to work around the robot's limitations to get the information they need.
One interesting idea could be exploring the backstories of the robots in more detail. For example, what were their initial programming thoughts and feelings before they started interacting with humans? Another could be imagining new types of robots that were not in the original I, Robot story, like robots with the ability to create art or music.
Maybe a story where a human engineer creates a highly intelligent robot. The robot becomes the human's closest friend and together they solve mysteries or go on adventures. The robot could have unique abilities that help them in their quests.
One interesting idea could be a crossover with "Moana". Elsa's ice powers and Moana's connection to the ocean could create a really cool dynamic. Maybe Elsa accidentally freezes part of Moana's ocean and they have to work together to fix it. Another could be with "Tangled". Rapunzel's long hair and her adventurous spirit combined with Elsa and Anna's journey in Frozen 2 would be exciting. Rapunzel could use her hair to help them climb mountains or cross chasms. A third idea is a crossover with "Beauty and the Beast". Belle's love for books and knowledge could help Elsa understand more about her powers and the history of magic in the Frozen world.
One idea could be creating a robot OC that has the ability to transform into different forms inspired by the various Grimm in RWBY. For example, it could shift into a Beowolf - like form for combat situations. Another idea is a robot OC designed by a villainous character in the RWBY universe but ends up having a change of heart and joins the heroes. You could also have a robot OC that has a unique Dust - based power system, which is different from the normal ways Dust is used in RWBY.
Another interesting concept is a robot OC that was created by a villain but has a change of heart. This robot could struggle with its programming and new - found sense of morality. It might have to hide its true identity from both heroes and villains while trying to do good in the world of BNHA.
A Rambo crossover fanfiction could involve him crossing over into the Star Wars universe. Rambo's guerilla warfare tactics could be interesting in a galaxy far, far away. Maybe he helps the Rebel Alliance in a ground - based battle against the Empire. Or a crossover with the Predator series. Rambo would be a worthy opponent for the Predator, and the fight between them in the jungle could be epic. Also, a Rambo and John Wick crossover would be intense, two highly skilled fighters on the same side or perhaps initially at odds.
One idea could be a crossover with a modern military setting. The Decepticons could be trying to steal advanced military technology. Another is a crossover with a post - apocalyptic world where they are competing with other factions for resources. A third could be a crossover with a magical realm, with the Decepticons trying to harness the magic for their own evil purposes.
One idea could be a crossover with Naruto. Kakuzu could be sent to the Naruto universe and form an unlikely alliance with a shinobi village to fight a common enemy, like the Akatsuki from his own world turned rogue in the new universe. This would create a lot of interesting character dynamics and battles.
Another option is a crossover with 'The Little Mermaid'. The characters from the descendants could meet Ariel and her friends underwater. Evie might be interested in the mermaid fashion and could design new outfits inspired by the underwater world.
Another possibility is a crossover with the world of Naruto. The characters from MHA could participate in the Chunin Exams. Bakugo might be really into showing off his skills in this new and different kind of competition.