One interesting example could be a crossover between the Autobots from 'Transformers' and the characters from 'Star Wars'. Imagine Optimus Prime teaming up with the Jedi to fight a common enemy. Another example might be a fanfiction where the Transformers cross over with the 'Marvel Universe', like the Decepticons trying to steal technology from Stark Industries. There could also be a crossover with the 'Lord of the Rings' world, where the Transformers help in the battle against Sauron.
In the realm of transformers crossover fanfiction, a really unique one could be a crossover with the 'Ghostbusters' universe. The Autobots and the Ghostbusters working together to deal with spectral threats that are somehow related to the Transformers' technology. Also, a crossover with the 'Men in Black' world, where the agents have to deal with the existence of the Transformers on Earth while also trying to keep it a secret from the general public. And then there's the idea of a crossover with the 'Power Rangers', where the Rangers and the Transformers join forces to protect the Earth from a super - powerful villain.
One idea could be that Lucifer, with his charm and manipulative skills, gets involved in the power struggles among the Autobots and Decepticons. He might try to use their war for his own amusement or to gain some sort of power. For example, he could offer a deal to Megatron to help him defeat the Autobots in exchange for something valuable in the underworld.
Maybe the Transformers end up in Remnant due to a space - time rift. The Grimm might be attracted to the Energon that the Transformers carry. The RWBY teams would have to team up with the Transformers to fight off both the Grimm and the Decepticons if they also show up. Yang could learn some combat moves from the Autobots, which would add a new dimension to her brawler style.
Well, a cool concept for a Ben 10 Transformers crossover fanfiction could be that the Transformers' AllSpark has a strange effect on the Omnitrix. This makes Ben able to transform into new alien - Transformer hybrids. For instance, Four Arms could become a huge hulking form with robotic arms that can transform into different weapons. Also, the Decepticons might try to steal the Omnitrix to use its power to create more powerful soldiers. Meanwhile, the Autobots would team up with Ben to stop them. Maybe there could be a situation where Ben has to use his alien forms' unique abilities in combination with the Autobots' skills to defeat a powerful Decepticon threat.
There might be a fanfiction where Master Chief somehow gets transported to the Transformers' universe. He has to adapt to the new world filled with giant robots, while also trying to find a way back home. Along the way, he befriends some of the Autobots and helps them in their fight against the Decepticons. This could involve a lot of cool crossovers of Halo and Transformers technology and tactics.
One idea could be that Sonic and his friends accidentally stumble into the world of the Transformers. Sonic's speed could be a valuable asset in a battle against the Decepticons. For example, he could quickly deliver important messages or parts between Autobots during a fight. Another idea is that the Chaos Emeralds somehow have an impact on the AllSpark, creating new powers or challenges for both the Sonic characters and the Transformers.
Another interesting concept is to have a character crossover. For example, Bumblebee from the Animated series could somehow end up in the world of the live - action Transformers movies. His small and agile form might be a big contrast to the more bulky Transformers in the movies. He could form an unexpected friendship with a human character, like Sam Witwicky, and together they could help the Autobots in the movieverse with a mission that requires his speed and intelligence.
One great example could be a story where the Autobots and Ponies team up to save their combined worlds from a common threat. Maybe the Decepticons have allied with some dark magic force from the My Little Pony universe. Another example might involve a pony accidentally stumbling into the Transformers' world and befriending Bumblebee. It could be a really cute and action - packed adventure as they try to find a way to get the pony back home while also dealing with the local threats in the Transformers' world.
One great example could be a story where the Spartans from Halo team up with the Autobots. They could fight against a common enemy like the Covenant and the Decepticons together. The Spartans' combat skills combined with the Autobots' strength and advanced technology would make for an exciting plot.
One interesting storyline could be the Power Rangers and Transformers teaming up to fight a common enemy that threatens both their worlds. Maybe a powerful alien force that can corrupt technology and has the ability to create its own powerful monsters. The Rangers' martial arts skills combined with the Transformers' brute strength and advanced weaponry would make for an epic battle.
Another interesting concept is a character - based crossover. A Joe like Snake Eyes could form an unlikely bond with a Transformer like Bumblebee. Snake Eyes' ninja skills could be used in combination with Bumblebee's speed and agility in combat. They might start off not trusting each other but gradually learn to work together as they face various threats.