One idea could be to explore Naruto's life in a modern human world. For example, he could be a college student trying to fit in while still having his ninja spirit. He might use his skills in parkour or martial arts competitions. Another idea is to anthropomorphize the ninja animals. So, like a talking and walking version of Akamaru, who could be a detective helping solve mysteries in the village.
A skunk could be a wizard in a magical world of anthropomorphic creatures. He has a small hut on the outskirts of a forest filled with magical herbs and potions. One day, a young deer comes to him asking for help because his village is being haunted by dark spirits. The skunk wizard uses his magic, which is often accompanied by a puff of his special scent, to banish the spirits and save the deer's village.
Well, a really interesting fanfiction features an anthropomorphic deer - girl. She lives in a secluded part of the forest that Naruto stumbles upon. At first, they have trouble communicating because of their different languages. But Naruto's determination to befriend her breaks through the barriers. Their story unfolds as they face challenges together, like protecting the forest from invaders. And in the process, they develop a deep and meaningful connection.
One common theme is friendship. Naruto is often shown forming strong bonds with the anthropomorphic characters. Another theme is adventure, as they embark on various quests together.
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.
One interesting concept could be the exploration of different cultures. For example, if a human is raised by anthropomorphic wolves, they might be exposed to a pack - like social structure with its own rules and hierarchies. Another concept is the development of unique relationships. The human and the anthropomorphic animals could form bonds that are a blend of friendship, family, and something entirely new. Also, it can show how the human adapts to the physical and cultural differences of living among these animal - like beings.
Another idea is that Aizen somehow ends up in the Naruto universe during the time of the Fourth Great Ninja War. He could try to manipulate both sides for his own gain. But Naruto, with his ability to see the good in people, might try to reason with Aizen and show him a different path. It could be a story of redemption or a great battle if Aizen refuses.
In a 'Naruto Mermaid Fanfiction', the mermaids could be in danger from an evil organization that wants to capture them for their precious scales. Naruto teams up with a mermaid princess to stop this threat and in the process, they learn about each other's worlds.
One idea could be a crossover where Naruto and Pucca end up in the same world due to a strange ninja jutsu gone wrong. Naruto is confused by Pucca's constant chasing of Garu, and he tries to help Garu escape in his own Naruto - style way.
Well, you could write a fanfiction where the Nine - Tails in Naruto has some sort of connection to a powerful entity in the Seraphim universe. This connection could lead to a series of events that require Naruto and the Seraphim characters to work together. Or perhaps a character from Seraphim is reincarnated as a ninja in the Naruto world and has to adapt to the new way of life while still having some of their Seraphim abilities.
One idea could be a blacksmith who creates unique ninja tools with special abilities that give the wielder an edge in battle. For example, a kunai that can change its shape during flight to avoid enemy defenses.