There are many possibilities. For instance, a fanfiction that focuses on Naruto's relationship with his father during his time as Hokage. What if Naruto found a way to bring back some of the characters who died in the main series? This could lead to some very emotional and interesting storylines. Also, a story about Naruto's adventures outside of the ninja world, like exploring different cultures and bringing back new knowledge to his village.
Well, you could write a fanfiction about Naruto and his friends having to face an ancient evil that was sealed away long ago but has now been released. Or perhaps a story in which Naruto has to deal with the consequences of a jutsu gone wrong that affects the entire Hidden Leaf Village. You could also explore a fanfiction where Naruto teams up with some of the villains from the series and tries to understand their motives.
Well, a cool naruto cartoon crossover fanfiction idea might involve Naruto crossing over with the Avengers. Imagine Naruto's ninja skills and the Avengers' superpowers combined to fight a common enemy. Also, a crossover with the world of Fullmetal Alchemist could be interesting. Naruto could learn about alchemy and how it differs from his ninja techniques. And a Naruto and Attack on Titan crossover, where Naruto uses his skills to fight Titans.
One idea could be a war between the Powerpuff Girls and the villains from Dexter's Laboratory. Maybe Mandark teams up with Mojo Jojo to create a super - weapon, and the Powerpuff Girls have to use all their strength and wits to stop them. Another idea is a war in the world of Adventure Time, where the Ice King tries to take over all the kingdoms in Ooo with an army of his ice minions. Finn and Jake would then lead a resistance against him.
Maybe the characters are brought together in a strange new world that's a mix of their own. The Powerpuff Girls could meet the Teenage Mutant Ninja Turtles. The Girls' superpowers and the Turtles' ninja skills would make for an exciting dynamic. They could fight against a new villain that threatens this combined world.
Perhaps a story where the cartoon all - stars are invited to a grand party in a different dimension. But things go wrong when a mysterious figure starts causing chaos at the party. They then have to work together to figure out who it is and stop them. This could involve a lot of comical misunderstandings and cool team - up moments.
A cool concept would be a crossover with 'Avatar: The Last Airbender'. Picture the Total Drama contestants in the four nations. Some might try to learn bending skills, like Duncan thinking he can be a great earthbender because of his tough - guy attitude. They could also get caught up in the Fire Nation's plots or help Aang in his journey to master all four elements. This would bring a whole new level of chaos and humor to both universes.
One idea could be to have the cartoon versions of the heroes and villains swap powers. For example, Iron Man could end up with Thor's lightning powers and Loki could have access to Captain America's super - soldier strength. This would lead to really unique battles and character development as they struggle to control new abilities.
Maybe a crossover with a fantasy - themed cartoon. The Mighty Ducks enter a magical world where they have to use their hockey skills in a whole new way. For example, they might play hockey on floating ice rinks in a land of wizards and dragons. They could also team up with the local characters to defeat a common enemy that threatens both their worlds.
Another plot idea is a time - travel story. Spider - Man gets sent back in time to when his uncle was still alive. He has to make sure that his actions in the past don't accidentally change the future too much while also trying to learn some valuable lessons from his younger self and his uncle. This could lead to some really emotional moments and also some interesting battles as he might face off against villains that were active during that time in a different way than he did in his own time.
One idea could be to put classic cartoon characters in a survival situation on a deserted island. For example, having Bugs Bunny and Daffy Duck having to find food, build shelter, and deal with the elements. Another could be a group of Powerpuff Girls trying to survive in a post - apocalyptic world full of mutated villains.
One interesting idea could be the combination of Naruto's ninja skills with mecha technology. For example, Naruto might use his chakra to power up the mecha in unique ways. Another idea could be the new enemies that are created specifically for this mecha - Naruto concept, like robotic shinobi that require different combat strategies compared to normal foes. Also, the design of the mecha Naruto itself can be really cool, perhaps with features inspired by the Nine - Tails.