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.
A more character - driven idea would be that Naruto and Yato meet and learn from each other's outlooks on life. Naruto, who has always fought for his friends and village, could teach Yato about the importance of having a strong community. Yato, who has a very different view of the afterlife and the divine, could show Naruto a whole new perspective on existence.
They could start by mistaking each other for enemies. For instance, when Naruto first meets Yato, he might think Yato is some kind of new - type of ninja using strange powers. Yato, on the other hand, could be confused by Naruto's strange appearance and chakra. But then they realize they have a common goal, like protecting innocent people.
Sure. One great naruto noragami fanfiction is 'Naruto in the World of Noragami'. It combines the unique powers and settings from both Naruto and Noragami in an interesting way. The characters from Naruto find themselves in the Noragami realm and have to adapt, which makes for some really exciting plotlines.
One interesting crossover could be a story where Naruto's world is invaded by ayakashi from the Noragami universe. Naruto and his friends have to team up with Bishamon's shinki. They would learn about each other's powers and cultures. For example, Naruto's ninjutsu might be a mystery to the Noragami characters, while the concept of shinki could be new to Naruto.
Naruto has the power of the Nine - Tails, which is a huge source of chakra. Bishamon has her own reservoir of divine power. In a fanfiction, they could combine their powers by having Naruto transfer some of his chakra to Bishamon, who then uses it to supercharge her attacks. Or vice versa, Bishamon could bestow some of her divine essence on Naruto, allowing him to access new forms or abilities that are a blend of both ninja and divine powers.
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 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.