King Kong would be an obvious choice. The epic battles between Godzilla and King Kong are well - known, and a fanfiction could explore different scenarios of their encounters, like what if they had to team up against a greater threat.
Mothra could also be a great crossover character. Since Mothra has a different nature compared to Godzilla, a fanfiction could focus on how their relationship develops in a new, crossover setting. Maybe they are forced to cooperate to protect their shared territory from an invading force.
From the Ultraman universe, Ultraman could be a very interesting crossover character. The contrast between Ultraman's more heroic, human - like form and Godzilla's massive, destructive presence could lead to a lot of interesting storylines. They could start off as enemies, with Ultraman seeing Godzilla as a threat to the planet, but then gradually realize they need to work together to face an even greater menace.
One idea could be Godzilla teaming up with other kaiju from different universes to fight a common, powerful enemy. Maybe an alien force that is threatening all kaiju-kind.
One potential crossover character could be Harry Potter. Imagine Naruto, with his immortality, meeting Harry in the wizarding world. Naruto could teach Harry some ninja skills, and they could fight together against Voldemort. Another could be Superman. The contrast between Superman's superpowers and Naruto's ninja skills, along with Naruto's immortality, would make for an interesting story.
Naruto himself could be a great crossover character. Since Kakashi is his mentor in the original series, seeing them interact when Kakashi is a kid could be really interesting. They could have a different kind of dynamic, with Naruto perhaps being the more experienced one in some aspects. Another potential character is Goku from Dragon Ball. The contrast between Kakashi's ninja skills and Goku's martial arts and superpowers would create a really exciting crossover.
Solid Snake is an obvious choice. Since they are from the same general franchise, their encounter could be filled with a lot of drama and action. They could have different views on how to handle certain situations, which would create great story tension.
Maybe Naruto from Naruto could be a crossover character. His ninja skills and Ichigo's combat abilities could create some unique fight scenes. Also, their different ideologies about friendship and power could lead to some great character interactions.
Another potential character is Harry Potter. His wizarding skills and knowledge of magic could be a contrast to Naruto's ninja abilities. Imagine Naruto in Hogwarts, learning about magic while also showing off his ninja moves. They could also face a threat together, like a dark wizard who is trying to use both magic and chakra for evil purposes.
King Kong is definitely one of the most popular. Their long - standing rivalry in the monster movie genre makes it a natural choice for fanfiction crossovers. Another popular one is Mothra. The relationship between Godzilla and Mothra in the original movies can be explored further or twisted in fanfiction crossovers. Also, characters from the Ultraman series are often crossed over with Godzilla. The different powers and abilities of Ultraman characters create interesting dynamics when pitted against Godzilla.
Goku from Dragon Ball could be a great crossover character. His Saiyan powers and love for combat could contrast and interact in an interesting way with Naruto's ninja skills and immortal sage abilities. They could have epic battles or team up against a common enemy.
Characters from 'Teenage Mutant Ninja Turtles' could be great. Imagine the Ducks and the Turtles teaming up to fight a common foe in the streets of New York. The Turtles' martial arts skills combined with the Ducks' hockey moves would make for an exciting story.
Definitely Sherlock Holmes. Since The Great Mouse Detective is inspired by Sherlock Holmes, a crossover with the original Holmes would be very interesting. They could compare and contrast their detective methods.