Sasuke is often a popular character in these fanfictions. He might play a role in helping Naruto against Madara or have his own motives during their battle. Kakashi can also be a prominent figure, perhaps using his Sharingan in a crucial moment to assist Naruto. Another popular character could be Hashirama, as his connection to Madara is a key part of the original story and can be further explored in fanfiction.
One common theme is the underdog story. Sakura is often seen as the underdog against the powerful Madara. So, many fics focus on her struggle and how she overcomes the odds. Another theme is the exploration of power levels. Writers often play around with how Sakura could match up to Madara's immense power.
There are definitely some out there. However, the quality can vary greatly. Some fanfics might be written by novice writers and have grammar or plot issues. But if you dig deep enough, you can find well - written ones. You could also try joining Naruto - related fan forums and asking for recommendations. People there are usually quite helpful and can point you towards some great 'sakura vs madara fanfic'.
Naruto would probably win. He has an indomitable will and has always found ways to overcome powerful foes. His experience and the unique powers he might gain with the Rinnegan could give him an edge over Madara.
One interesting plotline could be Naruto discovers a new form that gives him an edge over Madara. For example, a form that allows him to nullify Madara's Sharingan abilities. Another could be Madara having a change of heart due to Naruto's unwavering belief in him. Maybe he starts to question his own motives for destruction.
In such fanfiction, Sakura might be depicted as more alluring and perhaps more bold in her interactions with Madara. Madara could be shown as having a certain charm that draws Sakura to him.
Well, one possible outcome could be that Naruto and Sasuke manage to defeat Madara through their combined strength and newfound powers. They might use their signature jutsus in a coordinated way that Madara can't counter.
In such a fanfiction, Naruto and Sasuke might win. They are both extremely powerful and their combined strength, like Naruto's Rasengan and Sasuke's Chidori, could overpower Madara.