Well, one possibility is that Naruto has mastered some extremely powerful jutsu during the time skip. Maybe he's found a way to combine different elemental chakra in a new and unique way that gives him an edge in battles. He could be facing new, more menacing villains who are after his newfound power.
In this fanfiction, Naruto might have also developed some sort of connection with an ancient and powerful force. This could be something like a spirit or an old sage's power that was dormant until the time skip. As a result, his physical and mental abilities have skyrocketed, making him OP. He could use this power to protect the Hidden Leaf from threats that are emerging from other hidden villages or even from outside the ninja world.
There's also the possibility of a new, unknown threat emerging from a different dimension or realm. This antagonist could be a powerful being with abilities that the ninja world has never seen before. He sees Naruto's newfound power as a threat to his own plans of conquest and decides to target him first, leading to a series of epic battles across different locations in the Naruto universe.
One possible plot could be that Naruto returns from the training trip with new and extremely powerful jutsu. He surprises everyone in the village, including his friends and rivals. He then uses his newfound strength to take on tougher missions and protect the village from a new and powerful enemy that was previously too strong for the village to handle.
Perhaps Naruto is frozen as part of a time - stopping technique by a powerful enemy. In the fanfiction, the story could explore how the world around him changes while he's stuck. His enemies might take advantage of his frozen state to gain more power or territory, and his friends would be in a race against time to save him. They could face various challenges like other villages thinking Naruto's frozen state is a sign of weakness and trying to attack Konoha. Meanwhile, Naruto could be experiencing strange things in his frozen state, like being aware of his surroundings but unable to move or communicate.
I'm not sure specifically as there could be many different plots in a 'naruto is op academy' fanfiction. It might involve Naruto having overpowered abilities in an academy setting, like being able to use high - level jutsu easily while others struggle. Maybe he outperforms his classmates in combat training or academic studies due to his new - found op (overpowered) status.
One possible plot development could be Naruto focusing on rebuilding Konoha. He might use his newfound influence and power to inspire the villagers and make Konoha stronger than ever. Maybe he starts new training programs for the ninja of the village to better prepare them for future threats.
One possible plot development could be Naruto's internal struggle with the newfound power and responsibility. He might start to question his own limits and how to better protect the village in the future. Another could be the rebuilding of Konoha. Naruto could be deeply involved in the restoration efforts, both physically and mentally, trying to bring back the hope and strength to the villagers.
One possible plot development could be Naruto's efforts to rebuild Konoha. He might focus on strengthening the village's defenses and training new shinobi. Another could be his exploration of new jutsu, inspired by his battle with Pain. He could also work on improving relations with other villages.
Well, one possibility could be the rebuilding of the ninja villages. After the war, there would be a lot of destruction to repair. Maybe Naruto and his friends would take on leadership roles in this rebuilding process.
Perhaps Naruto forms new alliances in this 'naruto after the war crossover fanfiction'. He might team up with characters from other fictional universes who got involved because of the crossovers. They could work together to restore peace not just in his world but also in the worlds that have been connected through the crossovers.
Well, in many such fanfictions, a key plot development is Naruto's enhanced combat skills. Since he's trained by toads, he might learn new jutsu like more powerful toad - related techniques. His relationship with the toads also deepens, and this could lead to him having a better understanding of the Sage Mode. Maybe he discovers new ways to combine his regular ninjutsu with the toad - based training. Another aspect could be his growth in terms of leadership. As he gets stronger, he might inspire other characters in the fanfiction to follow his lead more, which in turn could change the dynamics of battles or the overall story's progression.