Yes, there are likely some Naruto fanfics out there with such a concept. You can start by looking on popular fanfic websites like FanFiction.net or Archive of Our Own. Just search for relevant keywords like 'jinchuuriki' and'reader' to find potential stories.
You can expect a story where the reader is in a very powerful position. Since having all the jinchuuriki means having access to a great deal of power. Maybe the reader will use this power to protect the Hidden Villages, or to face off against powerful enemies like Madara or Kaguya.
One possible plot could be a great battle against a common enemy. Naruto, with his experience and leadership, could bring all the Jinchuuriki together. They might combine their unique powers, like the different types of chakra from each Bijuu. For example, the Nine - Tails' chakra is known for its great strength and speed. Together, they could form a powerful force to protect the ninja world from a new, overwhelming threat that no single village or individual could handle alone.
The Jinchuuriki come from different villages and backgrounds, which shapes their personalities. Naruto, with his goal of unity among all ninja, would try to bring out the best in each of them. There could be a Jinchuuriki who is very proud and haughty because of the power of their Bijuu. Naruto would have to use his own charm and tenacity to make them see that they are all equal in this group. In the end, their individual personalities could blend into a unique group dynamic where they support and complement each other, despite their differences.
Obviously, Naruto is one of the main characters. And the other Jinchuuriki would also be main characters. For example, Gaara, who was the Jinchuuriki of Shukaku. There could also be Killer Bee, the Jinchuuriki of the Eight - Tails. These characters are important as they each have their own unique abilities and personalities.
In a fanfic where Naruto is the Sanbi Jinchuuriki, he might have different powers. The Sanbi gives abilities related to water and some unique forms of chakra control. Naruto could potentially use these new powers to create more diverse and powerful jutsu. For example, he could combine his already strong wind - style jutsu with water - style jutsu enhanced by the Sanbi's power, making his attacks more unpredictable and deadly.
In this fanfiction, Naruto Jinchuuriki might have god - like powers such as extreme strength. They could potentially have the ability to control nature on a large scale, like summoning massive storms or earthquakes. Their physical endurance might be enhanced to the point where they can withstand attacks that would normally be fatal.
Well, it implies that Naruto would have a huge burden and responsibility. Since each bijuu has its own personality and power, Naruto would need to balance and manage them all. He might face internal struggles as the bijuu's wills could conflict. In terms of the story, it would open up a world of possibilities for him to explore new forms of jutsu and power-ups. Maybe he could use the combined strength of all the bijuu to protect the entire ninja world from threats that were previously unbeatable.
Well, in this kind of fanfic situation, Sakura could also become more protective of Naruto. Since a jinchuuriki is in a rather dangerous position, she might start to see him as someone who needs her support more than ever. She could try to keep his secret safe from those who might want to harm him because of it.
Their conversations could lead to greater unity among the villages. Since the Jinchuuriki represent power in their respective villages, if they communicate well, they can promote better relations between the villages. For example, if the Jinchuuriki from the Sand and the Leaf become friends through these conversations, it can ease the historical tensions between the two villages.