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 in the fanfiction world is that Naruto is exposed to an ancient scroll or artifact that contains the secrets of paper jutsu. This could be something he stumbles upon during a mission or an exploration. Once he accesses this knowledge, he spends time studying and practicing it, gradually mastering the art of using paper jutsu. It might also be tied to a prophecy or a special destiny that he has, which leads him to this unique form of jutsu.
He could use it for stealth. For example, he could create paper clones that are much quieter and less detectable than his normal clones. These paper clones could be used to spy on enemies or gather information without being noticed easily.
He could potentially learn the Flying Thunder God Technique. It's a very powerful jutsu that Minato was famous for. Naruto's already fast with his Sage Mode and Nine - Tails Chakra, and this would make him even more formidable in battle.
Well, in many such fanfictions, Naruto might start learning his father's jutsu when he discovers some hidden scrolls or when a mentor who knew his father decides to teach him. Maybe it could be someone like Jiraiya who reveals some secrets about his father's techniques.
Maybe he found some hidden scrolls left by his mother. These scrolls could have contained the details of her jutsu. Naruto, being the curious and determined ninja he is, would have studied these scrolls carefully and learned the jutsu.
In fanfiction, the reanimation jutsu might have extended or modified limitations. For instance, in the original, there were clear rules about the caster's control over the reanimated. But in fanfiction, a writer could create a scenario where the reanimated can break free of that control more easily. Also, the source of the sacrifice for the jutsu could be different. In the series, it was usually human sacrifices, but fanfiction might explore using other forms of energy or substances.
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.
In Naruto fanfiction, cheat codes can drastically change the use of jutsu. They might allow a character to instantly master a jutsu that usually takes years of training. For example, a cheat code could give Naruto the ability to use the Rasengan without any training from Jiraiya. It's a fun concept that adds an interesting twist to the Naruto universe.
In fanfiction, the world of Naruto is often expanded upon. Regarding Naruto's ability to copy jutsu, it can be a central plot point in some stories. For example, a fanfiction might have Naruto encounter a powerful enemy with a jutsu he's never seen before. His ability to copy it could be the key to his victory. Or perhaps the fanfiction explores the consequences of Naruto copying too many jutsu, such as losing control of his chakra or having his own identity as a ninja become muddled because he's using so many different copied techniques. There are countless possibilities when it comes to Naruto's jutsu - copying ability in fanfiction.
Well, it could be the Uzumaki Chain jutsu. In the Naruto lore, the Uzumaki clan had some unique abilities and the chain jutsu was one of them. His mother Kushina was from the Uzumaki clan, so it's possible that's the jutsu he learned in the fanfiction.
He could practice in secret locations where no one can see him. For example, in an abandoned cave or a hidden part of the forest. That way, no one will know about the new jutsu he's developing.