I don't know of any anime that has the theme or plot of " defeat the monster and turn it into a card." Perhaps this kind of plot appears in novels or games, but I've never heard of any anime with such a theme or plot.
Perhaps it was because of the power he amassed in the process of defeating Voldemort. In the fanfic world, power can be a very scary thing to those in authority. Harry's new - found and possibly overwhelming power could have made the existing magical power structure feel threatened. So, they arrested him as a way to control and contain that power, rather than seeing him as a hero who saved the wizarding world.
Often, Naruto's relationships with other characters are explored further. He might have deeper conversations with Sasuke, trying to convince him to come back to the village for good. His bond with Sakura could also develop in different ways, perhaps becoming a stronger friendship or even something more romantic in some fanfictions.
This question was related to a classic anime plot, the " Death Card " in Final Fantasy 7.
In Final Fantasy 7, the protagonist Claude and his friends had to fight powerful monsters to save the world. After every battle, the monster would turn into a card. These cards had great power to help the protagonists realize their wishes.
When Claude and his friends finally defeated all the monsters, they got a special card. This card was their symbol of victory. But when they opened the card, they found a line of words written on it: "Only a real warrior can open this card."
This story tells us that even if we defeat all the monsters, we still need to have the courage to stick to our beliefs. Only a true warrior could open this card and gain strength and wisdom from it.
He might have been put on trial. The wizarding court would then decide his fate based on the evidence presented against him. If the court was corrupt or influenced by those who feared Harry's power, he could be wrongly convicted.
Well, one possible plot could be Naruto coming back to the village and being hailed as a hero. He might then focus on rebuilding the parts of the village that were damaged during the Pain attack. He could also start training the next generation of ninja, sharing his newfound wisdom and strength.
Another development could be that Naruto starts to understand the world outside the Hidden Leaf better. His encounter with Pain, who had his own ideology about peace, makes Naruto question his own views. So, he might embark on journeys to other villages to learn more about different cultures and ways of achieving peace, which in turn changes his perspective on many things.
In this kind of fanfiction, Naruto might be welcomed as a hero. The village could start to rebuild with his leadership. People would look at him with newfound respect and admiration.
It could be a rogue ninja from another village who sees Naruto's victory as a threat to their own plans. Maybe they were planning some sort of takeover or power play and Naruto's new - found status throws a wrench in their plans.