In many fanfics, Naruto gets stronger through unique training regimens. For example, he might encounter a powerful mentor who teaches him new jutsu or ways to enhance his chakra control. This could involve intense physical and mental exercises that push his limits far beyond what he learned in the original series.
In fanfiction, Ichigo might get stronger through unique training regimens. For example, he could be trained by a long - lost powerful Shinigami. This Shinigami might have ancient techniques that are not known to the regular Soul Society. Ichigo would have to endure rigorous physical and spiritual training, pushing his limits far beyond what he thought possible.
The plot of 'I get stronger by eating magic stones' light novel probably revolves around a protagonist. This person discovers that eating magic stones gives them strength. As they start on this journey, they might encounter other characters who either want to steal their magic stones or are also interested in this strange power - up method. They could get involved in battles to protect their source of strength or explore places where magic stones are found.
Since I haven't read this particular light novel, it's hard to say for sure. However, there is usually a central character in such stories who discovers the ability to get stronger with magic stones. There could be friends or allies that this main character meets along the way. Maybe there's an antagonist too, someone who wants to stop the protagonist from getting stronger or wants to use the magic stones for their own evil purposes.
Often, in fanfic, Naruto gets stronger by delving deeper into his Uzumaki heritage. Since the Uzumaki clan was known for their large chakra reserves, he could learn to fully tap into this potential. This might involve special training techniques passed down within the clan that were previously lost or forgotten.