One idea could be a Lego crossover between Star Wars and Harry Potter. Imagine Lego Darth Vader facing off against Lego Voldemort. Another could be a crossover with superheroes like Lego Batman teaming up with Lego Iron Man to save Lego Gotham and Lego New York. Or a crossover of Lego Pirates of the Caribbean with Lego Lord of the Rings, with Jack Sparrow and Aragorn on an adventure together.
One idea could be a crossover with another Lego theme like Ninjago. The characters from Chima could find themselves in the world of Ninjago and have to learn new fighting styles. For example, Laval might team up with Kai to fight a common enemy. Another plot could involve a time - traveling crossover. Chima characters go back in time and meet their ancestors, which could lead to all kinds of adventures as they learn about their heritage. A third idea is a crossover with a non - Lego fantasy world. The Chima characters enter a world full of magic and mythical creatures, and they have to use their own unique skills to survive and make new friends.
One idea could be a crossover with other Lego themes like Ninjago. The Monkie Kid characters could team up with the Ninjago ninjas to fight a common enemy. For example, a powerful dark force that threatens both their worlds. They could combine their unique skills and powers, like Monkie Kid's staff skills and the ninjas' elemental powers.
A plot could revolve around a time - traveling aspect in Lego City Undercover fanfiction. The protagonist accidentally activates a time - traveling device and ends up in the past of Lego City. They have to find a way to get back to their own time while also making sure not to change the past in a way that would destroy the future of the city. This would involve a lot of exploration of Lego City's history and its evolution over time.
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.
Well, in a Lego lemon fanfic, you could have a lemon - loving Lego character who tries to convince all the other Lego people in his town to start growing lemon trees made of Lego bricks. Or perhaps there's a mystery involving a stolen lemon - scented Lego piece and the main character has to solve it. There could also be a story where a Lego scientist discovers that lemon juice can be used to power new types of Lego vehicles.
One idea could be the ninjas traveling back in time to the very beginning of Ninjago's creation. They could witness the forging of the Golden Weapons and try to prevent an evil force from stealing them at that time. This would change the whole course of Ninjago's history and create a whole new set of challenges for the ninjas.
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.