A jutsu that allows the user to transform their chakra into a liquid form that can seep into the ground and then resurface anywhere within a certain radius as a surprise attack. Another could be a jutsu that uses sound waves to disrupt an opponent's chakra flow, like a high - pitched noise that throws off their concentration and ability to perform jutsus.
A 'Solar - Flare Rasengan'. Naruto could combine his wind - style chakra with some kind of solar - based energy he discovers. This jutsu would be like a super - charged Rasengan that emits a blinding light as well as powerful wind - based damage.
Often, the unique feature is the expansion of the jutsu's capabilities. For example, in some fanfictions, the Shunshin no Jutsu can be combined with other elements like fire or water jutsus.
In certain Naruto sealing jutsu fanfictions, there are sealing jutsu that can manipulate time within a small area. For example, a seal is placed on a room, and inside that room, time moves either faster or slower. This is a very creative take on sealing jutsu as it combines two different concepts - sealing and time manipulation. It can be used for training purposes or as a trap in the story.
One interesting idea could be exploring new and unique ways the expansion jutsu can be used in battles. For example, using it not just for physical size increase but also for expanding the range of other jutsus.
Naruto might improve the Sexy Jutsu by using chakra in a more creative way. He could use it to create an illusion of a more alluring environment around him during the jutsu, like a beautiful garden or a luxurious room. This would enhance the overall effect of the jutsu.
Some fanfictions might explore the idea of combining Forbidden Jutsus. Picture a scenario where a rogue ninja combines a Forbidden Jutsu of destruction with a Forbidden Jutsu of mind control. This could create a super - powerful and extremely dangerous new ability, and the story could follow the efforts of the main characters to stop this new threat.
One interesting idea could be the reanimation of minor characters from the Naruto series and exploring their backstories that were not fully told in the original. For example, reanimating a random shinobi from a minor clan and showing how their clan's unique abilities could have been used more effectively in the war. Another idea might be the reanimation of characters from different time periods in the Naruto universe's history, like shinobi from the era before the Hidden Villages were established.
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.
Well, perhaps a plot where the harem no jutsu is used not just for comical effect but to actually solve a complex political situation in the Naruto world. The various characters in the 'harem' could use their unique skills and influence to bring about peace. It could also be interesting to see how Naruto manages this new dynamic among the characters in his 'harem' and how it changes his relationships with them on a deeper level.
Perhaps in the fanfiction, Naruto perfects the Sexy Jutsu to the point where it can be used for espionage. He could transform into a seductive character and infiltrate enemy strongholds, gathering valuable information without being detected. This would add a new dimension to his ninja skills.