Well, in certain fanfic scenarios, Naruto could learn paper jutsu as a result of some experimental training. For example, he might be trying to combine different elements of his existing jutsu and accidentally discovers a way to manipulate paper. It could be that his chakra takes on a new form during a particularly intense training session and he realizes he can control paper with it.
One possibility could be that Naruto discovers a hidden ability within himself to use Wood - Style Treant Jutsu. Maybe he unlocks it during a life - threatening battle where he needs to protect his friends. He could combine his own chakra with some ancient energy source in the forest to create these powerful treant - like creatures that fight on his side.
One cool jutsu could be the Water Spiral. Naruto would spin water around his body at a high speed, creating a protective and offensive spiral. Another could be the Water Mirror Clone. He creates clones made of water that can reflect attacks back at the enemy. And there's the possibility of the Water Tsunami, where he summons a huge wave of water to overwhelm his foes.
Character development related to water style is also a big part. The characters might struggle to control their water style powers at first, like a young ninja learning to harness the power without losing control. And they may also have a deep connection to water, like feeling a sense of calm when near a body of water which enhances their abilities.
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.
Jiraiya could be one. Although he is known more for his fire and earth - based jutsu, he has vast knowledge and could guide Naruto in using water affinity in unique ways. Another could be Kisame. He is a master of water jutsu. His skills with water manipulation are top - notch, and he could teach Naruto some really powerful and advanced water techniques.
The Water Dragon Jutsu could be modified to carry other elements within it. For example, the user could infuse lightning chakra into the water dragon. So when the dragon attacks, it not only hits with the force of water but also delivers electric shocks. This would be a great new battle strategy as it combines two different elements for a more powerful and unexpected attack.
The fanfic could start with Naruto having a strange dream about using Wood - Style Treant Jutsu. He wakes up curious and starts to experiment. He finds that he can transfer his own emotions into the treants, making them more aggressive or defensive depending on how he feels. As he gets better at it, he uses the jutsu in a major battle against a group of rogue ninjas who are terrorizing a village. His treants become a symbol of hope for the villagers as they fight off the invaders.
Maybe Sasuke. Although they are rivals, they also have a deep bond. Sasuke might have come across a unique jutsu during his travels and decide to teach it to Naruto so that they can both become stronger and better protect their village.
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.