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.
Another interesting jutsu could be the 'Time Warp Clone Jutsu'. Naruto would create clones that exist in a slightly different time frame. These clones could act as scouts, seeing a few seconds into the future or past of a battle situation. They could then relay this information back to Naruto, giving him a strategic advantage.
If Naruto invented the 'Energy Absorption Jutsu', it could change the plot significantly. He could absorb the chakra or energy of his enemies, weakening them while strengthening himself. This would make him an even more formidable opponent and could potentially shorten battles, as he could quickly disable foes.
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.
Sasuke could be one of the people to teach Naruto new jutsus. They have a friendly rivalry and Sasuke has some unique jutsus like his Rinnegan - related abilities. He could teach Naruto some aspects of the Rinnegan's power, or at least how to counter it more effectively which could be considered a new 'jutsu' in a sense.
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.
There's also the 'Inferno Storm Jutsu' in some fanfictions. It creates a large - scale storm made entirely of fire. The fire in this storm has different intensities, with the center being the hottest and most destructive. It can cover a large area, making it a great offensive move against groups of enemies.
There could be a jutsu that allows for instant teleportation across long distances. This jutsu might be a new discovery in the fanfiction world, perhaps created by a character who has been experimenting with space - time ninjutsu. They might use it to quickly get in and out of battles or reach far - off places in a blink.
He might learn a time - traveling jutsu. This would be really cool as it could allow him to go back and change certain events in the Naruto world, or gain knowledge from the past to use in the present battles.
For Hinata, Naruto might create a jutsu that helps her enhance her Byakugan's range and clarity even further. It could also have a defensive aspect where she can project a shield made of chakra visible only to those with the Byakugan. For Shino, a jutsu that makes his bugs more resistant to enemy jutsus and also gives them the ability to track opponents over long distances. For Sasuke, a jutsu that combines his fire - based attacks with lightning in a more seamless way, creating a new and more powerful element.
One creative interpretation could be a new form of Rasengan. Maybe a Rasengan that can split into multiple smaller ones upon impact, like a cluster bomb. This would be a powerful jutsu as it could cover a wider area and hit multiple targets at once.
One creative interpretation could be a story where Naruto discovers a new form of the healing jutsu that can not only heal physical wounds but also emotional traumas. This could lead to him helping characters like Sasuke heal the deep - seated emotional pain from his past.