One interesting plot could be a character with shadow release power being able to manipulate the shadows of ancient beasts. This would create a whole new level of challenges and adventures as they try to control these powerful and unpredictable forces.
One idea could be a story where a new character discovers a unique chemical release ability that no one has seen before. They could use it to solve a mystery in the Naruto world, like finding out who is secretly poisoning the water supply in a village. Another plot could involve a villain using a chemical release jutsu to create a dangerous fog that makes everyone hallucinate and fight each other. Then Naruto and his friends have to find a way to counter it.
Well, consider a plot where there's a village hidden in the snow that has been cut off from the rest of the ninja world. The people there have unique Snow Release abilities. Naruto and his friends discover this village during a diplomatic mission gone wrong. They have to figure out how to communicate with the villagers and also deal with the fact that some of the villagers see them as threats due to their different ninja powers. The Snow Release fanfiction could then focus on the cultural exchange and the battles that follow.
One plot idea could be a young shinobi discovers they have the magma release ability in a hidden village. They struggle to control it at first, causing chaos in the village. But with the help of an old master, they learn to harness it for good, like protecting the village from a powerful enemy invasion.
One idea could be exploring an alternate timeline where the main characters have different allegiances. For example, Sasuke could side with Orochimaru permanently and Naruto has to find a way to bring him back without fighting. Another could be a story where the Akatsuki are actually working for a greater good that was misinterpreted, and Naruto teams up with them to fight a common enemy.
One interesting plot idea could be Naruto using his shadow clones to time - travel back to the era of the First Hokage. He could then use his modern - day knowledge and shadow clone jutsu to help shape the early history of the Hidden Leaf Village.
In the fanfiction, the crystal release bloodline could be linked to a hidden realm made entirely of crystals. The main character, who has this bloodline, discovers a way to enter this realm and finds out that there are powerful crystal beasts there. They have to form an alliance with some of these beasts to gain enough power to defeat an evil force that is threatening the ninja world.
Well, a really cool plot might be that Naruto, in his search for more power to protect the village, stumbles upon an ancient scroll that details a nuclear - release type of power. However, this power is extremely dangerous and he has to train in a secret location away from the village. Along the way, he meets a hermit who once tried to master this power and was scarred by it. Naruto then has to decide if he should continue to pursue this power or abandon it for the safety of everyone. This would lead to a lot of character development and internal struggle for Naruto.
One idea could be a fanfiction where Naruto discovers a new form of Fire Release that is so massive it can change the landscape of a battle. For example, he could use it to create a huge wall of fire to protect the Hidden Leaf Village from a powerful enemy invasion.
One idea could be a story where the main character discovers a new form of Wood Release that has unique powers, like the ability to heal entire forests. This could lead to a conflict as others try to control or steal this power.
One idea could be a story where a new character discovers they have the Black Fire Release ability and must learn to control it while being hunted by an evil organization that wants to use it for their own gain.