I'm not entirely sure as it depends on the specific fanfiction. But it might involve Naruto having some sort of connection to Homura, perhaps in an alternate universe where Naruto's lineage is related to Homura in unexpected ways.
Another theme is the exploration of different powers. Naruto has his ninja techniques and Homura has her own unique abilities. Fanfictions often play around with how these powers interact, like if they could combine their powers to create a new and powerful technique.
Obviously Naruto would be one of the main characters. And if he's the son of Homura, then Homura would also be a key character. There might also be the usual Naruto characters like Sasuke and Sakura who would be involved in the story in some way.
Yes, there are quite a few. Some focus on exploring an alternate universe where Homura is male and his relationship with Madoka takes on new and unique dynamics. For example, in some fanfictions, they might go on adventures together in a world filled with different magical threats compared to the original anime.
Love is also a prevalent theme. Whether it's platonic or romantic love, it's a major aspect. For example, some fanfics show how their love for each other can overcome great obstacles. And there's often a theme of redemption as well, especially for Homura who has made some morally complex decisions.
The theme of redemption can also be found in some Homura x Kyubey fanfiction. Even though Kyubey has caused a lot of harm, some stories might explore the possibility of his redemption. Maybe through Homura's influence, Kyubey starts to see the error of his ways. Or perhaps Homura realizes that Kyubey is just a product of his species' nature and tries to find a way to change that nature, which could be seen as a form of redemption for both of them in a way.
One popular 'homura light novel' series could be 'Homura's Adventure'. It follows the protagonist Homura through a fantastical world filled with magic and mystery.
One interesting story could be about Naruto and Homura teaming up on a special mission. They might use their unique skills, Naruto with his ninja techniques and Homura with her own abilities, to overcome various challenges and enemies along the way.
Another theme is self - discovery. As they interact, they might learn more about themselves. For example, Hitomi could discover a more confident side of herself through her relationship with Homura. And Homura might find a softer side to her own personality. In some fanfictions, they help each other grow as individuals.