In the Noragami universe, there's no indication that the characters themselves watch fanfiction. Fanfiction is a creation by the fans for the fans in our world, not something that exists within the fictional world of Noragami for the characters to access.
One common theme is the exploration of different power systems. Since both Naruto and Noragami have their own unique power structures, fanfictions often play around with how these powers interact or contrast. For example, Naruto's chakra system and Noragami's divine powers.
One popular theme is the exploration of the relationships between the characters. For example, the complex bond between Yato and Hiyori. Another theme is the expansion of the Noragami world, like delving deeper into the lore of the heavens and the far shore. Also, there are often stories that focus on character backstories, such as how Yukine came to be Yato's shinki.
One common theme is the idea of redemption. Yato has his own past and flaws, and often in these fanfictions, the female character helps him on his path to redemption. For example, she might encourage him to face his past mistakes and become a better god.
FanFiction.net also has Noragami fanfictions. It's been around for a long time and has a wide range of works. Some of the stories might be a bit older but still very interesting. You can search by genre or character to find what you like.
If the Noragami characters watched fanfiction, it would be a chaotic situation. They would encounter different versions of themselves, some might be flattered by positive portrayals while others could be offended by out - of - character interpretations. Yato, for instance, might be amused or bewildered by fanfictions that depict him in new and unexpected ways. Hiyori, on the other hand, might be shocked by fan - made stories that deviate from her own understanding of her role in the Noragami world. And the gods might be generally perturbed by the liberties taken in fanfiction with their divine natures and the world they inhabit.