One idea could be a crossover with the Marvel Universe. Beerus could visit Asgard and have an encounter with Thor. Maybe they have a friendly competition over who is stronger in terms of combat skills or who can handle more powerful magical items. Another could be a crossover with the Harry Potter world. Beerus might be intrigued by the magic there and get involved in a battle against Voldemort, using his godly powers in a completely different magical setting.
A cool Beerus crossover fanfiction idea is to cross him with the world of Pokémon. Beerus arrives in the Pokémon world and is both amused and frustrated by the Pokémon battles. He might decide to train a Pokémon to be the strongest in the world, using his own unique training methods. Or he could cross over with the DC Universe and meet Superman. Their encounter could involve a test of strength and a debate about protecting their respective universes.
Another interesting concept is a crossover with the Star Wars universe. Beerus could find himself in the middle of the conflict between the Jedi and the Sith. His neutral stance in the beginning could change as he discovers the true nature of the Force. Maybe he decides to side with one group or tries to end the conflict in his own unique way, which would be a fascinating exploration of both universes.
One idea could be a story where Beerus and Kaioshin have to team up to face a new and powerful enemy that threatens their universe. They start off with their differences but gradually learn to work together and respect each other's powers.
One idea could be a cooking competition between Beerus and Champa. They could each bring their own unique ingredients from their universes and compete to make the most delicious dish. It would be a fun way to show their rivalry in a different light.
One idea could be that Beerus is intrigued by Bulma's intelligence and her ability to create amazing inventions. He might start visiting her more often, causing some comical misunderstandings among the Z - fighters. For example, Vegeta could get jealous of their interactions.
For a Beerus OC in fanfiction, it could be an OC who was once a normal cat - like creature on a destroyed planet. Beerus, out of pity or some unknown reason, bestowed some of his power on this creature. As a result, the OC gradually evolved into a powerful being with some of Beerus's characteristics. This OC could have a very different personality from Beerus, being more kind - hearted and using their power to help revive planets rather than destroy them.
Maybe there's a plot where Beerus has a premonition about a threat to the universe that only Bulma's technology can help prevent. So, he has to team up with her. Along the way, they learn more about each other's worlds. Bulma gets to understand the power and responsibilities of a god like Beerus, and Beerus discovers the amazing potential of Earthling technology. This could lead to a deeper friendship or mutual respect between them.
One interesting Beerus fanfiction could be about his origin before he became a Destroyer. It might explore his training and the events that led him to such a powerful position.
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.
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.