He could invent a new type of transportation device, like a flying platform that ninjas can use to quickly move around. It would be powered by chakra and could be controlled with simple hand gestures.
In a 'Naruto is an inventor' fanfiction, Naruto could invent a chakra - powered healing device. Given his experiences of seeing his friends get hurt, he would be motivated to create something that can quickly heal wounds. This device could work by emitting a special type of chakra wave that stimulates the body's natural healing process, and it could be small enough to be carried around easily during missions.
Well, there could be inventions like new types of kunai. Maybe Naruto invents kunai that can change direction mid - flight or kunai with some sort of elemental power attached to them. Another thing could be new training equipment. He might create a training ground that can simulate different battle scenarios based on the user's chakra input.
One jutsu he could invent is the 'Elemental Mimicry Jutsu'. With this, Naruto could temporarily take on the properties of any element he has encountered. For example, he could become as fluid as water to slip through attacks or as solid as earth to withstand powerful blows.
Yes, there are likely to be such fanfics. The Naruto universe has a rich lore and diverse characters, which provides a great backdrop for creative interpretations like Naruto being an inventor. Fans often like to explore different aspects of their favorite characters, and making Naruto an inventor could lead to some really interesting stories, perhaps with him inventing new jutsu - techniques - or devices to help in battles or improve life in the Hidden Leaf Village.
One common theme is self - discovery. Naruto often discovers his potential as an inventor while trying to solve problems in the ninja world. Another theme is innovation. Fanfics usually focus on Naruto creating new and unique ninja tools or techniques. Also, friendship can be a theme, like when Naruto teams up with his friends to develop inventions.
In fanfiction, Harry could invent a spell to protect his mind from external intrusion. Considering all the times his mind has been targeted in the original series, this would be a very practical spell. He might also create a spell to enhance the growth of magical plants. Since he has had some experience with Herbology, this would be an area where he could contribute with his spell - inventing skills. Additionally, a spell to quickly repair broken magical items could be one of his inventions, as he has often had to deal with damaged or broken things in his adventures.
He might invent defensive spells. Considering his history of facing dark forces, he could come up with spells that protect against specific dark magic attacks, like a spell that creates an invisible shield against the Cruciatus Curse.
Maybe he invents a gun that can fire chakra - enhanced bullets. This way, it combines the power of ninjutsu with the concept of a gun.
Unique inventions. If the fanfiction has really cool and original inventions that fit well into the Naruto world, it stands out. For example, an invention that can manipulate chakra in a new way.
One great Naruto genius inventor fanfiction could be 'The Ingenious Ninja Inventor'. In this fic, the main character, a young ninja with a knack for invention, creates all sorts of amazing devices that change the way battles are fought in the Naruto universe. His inventions range from advanced shuriken launchers to chakra - powered armor.
I'm not sure about a specific 'Naruto is an inventor' fanfiction. But generally, in such fanfictions, Naruto might invent things like advanced ninja weapons. He could create a new type of shuriken that has the ability to change its shape mid - flight, adding an unexpected element to his battles.