In many fanfictions, Naruto might use new jutsus or a deeper understanding of his own power. Maybe he taps into a more powerful form of the Nine - Tails' chakra and combines it with his Sage Mode in a unique way to overpower Pain.
In some fanfictions, Naruto's pain might manifest through his actions. For example, he could become withdrawn and isolate himself from his friends. This is because Naruto has always been a social person, so any deviation from his normal behavior could be a sign of his internal pain.
One possible cause could be his sense of failure. Naruto always wants to protect his friends and village, so if he fails in a mission or is unable to save someone, it can cause him great pain.
His fighting style could become more aggressive. Without the fear of pain, he might be willing to use more extreme techniques that would otherwise be too dangerous because of the pain they cause to the user. He could push his body to the limit more often.
Konan could be really interesting. In some fanfictions, she might have a different backstory or motivation that affects the Naruto vs Pain fight. For example, she could be secretly trying to stop Pain from going too far in his destruction of the Leaf Village.
Jiraiya could be a great addition. Since he was Pain's teacher, his presence could add a lot of depth to the story. He could offer insights into Pain's past and also help Naruto understand Pain better.
Perhaps in this fanfiction, Naruto is facing an enemy who can manipulate the forest against him. So, he decides to communicate with the trees to form an alliance. The trees, understanding Naruto's pure heart, agree to help him. Together, they create a strategy to defeat the enemy. Naruto might also learn new techniques from the trees, like how to use the roots as a defense mechanism.
Yes, in some fanfiction, Naruto might be depicted as singing 'Everybody Talks'. Fanfiction often takes creative liberties and can put characters in unexpected situations, like singing a popular song.
The plot could involve Naruto having a philosophical discussion with Danzo. Naruto, with his idealistic views of peace and friendship, might try to sway Danzo from his more ruthless ways. They could talk about power, sacrifice, and what it really means to be a shinobi. Naruto could also demand answers from Danzo about the secrets he's been hiding from the village.
Maybe in the fanfic, Naruto is on a mission to retrieve some important information that Sasori has. When Naruto talks to Sasori, it turns into a battle of wits. Sasori tries to deceive Naruto with false information while Naruto uses his intuition and sharp mind to see through the lies. Along the way, they also discuss their different upbringings and how it shaped their current selves.