One idea could be that the Enchantress uses her powers to help Naruto gain a new form. Maybe she is intrigued by his determination and decides to enhance his chakra in a unique way that gives him an appearance similar to her own magic - with glowing markings and enhanced speed. Another could be that she gets lost in the Naruto world and Naruto has to help her get back home, during which they form an unlikely bond.
A possible plot is that the Enchantress is a being from a parallel dimension where magic is the dominant force. She accidentally opens a portal to the Naruto universe. Naruto, being the curious and friendly ninja he is, approaches her. She initially tries to use her enchantment powers on him but fails because of his strong will. Instead, they start to communicate. Naruto then shows her the beauty of his world, and she in turn teaches him some basic magic concepts, which he then uses in combination with his ninja skills to face a new and powerful enemy.
A really interesting plot could be that Bella, as an enchantress, accidentally casts a spell on the whole town that makes everyone act out their deepest desires. This leads to chaos as people start behaving in strange and unexpected ways. Bella then has to find a way to reverse the spell while also dealing with the consequences of her actions and learning more about her powers in the process.
One idea could be that the OC is a new hero in the DC universe. The yandere Enchantress becomes obsessed with the OC because of their unique powers. She starts to manipulate situations to be around the OC more, like causing villains to attack near where the OC is so she can 'help' and get closer to them.
Perhaps Naruto and Lala meet during a mission where Naruto is sent to a different dimension. Lala, being from an alien world, is intrigued by Naruto's determination and they form an alliance to face a common enemy in that dimension. Their different powers and abilities complement each other, and as they work together, they start to develop feelings for each other.
A more complex plot could be that there is a prophecy in both worlds about a union between someone from the Naruto universe and someone from Ruby's universe. Naruto and Ruby are the ones fated to fulfill this prophecy. They initially don't get along but as they face various challenges together, they start to understand each other and fall in love, while also saving both their worlds in the process.
In a naruto x avatar fanfiction, there could be a scenario where the Akatsuki from Naruto's world teams up with some of the villains from the Avatar world. This would force Naruto and the Avatar (whichever one it may be) to put aside their differences and form an alliance with other characters from both worlds to stop this powerful and evil coalition.
One idea could be that a zombie virus spreads in the Naruto world. Naruto and his friends have to not only fight the zombies but also figure out how the virus started. Maybe Orochimaru was experimenting with dark jutsu and it went wrong.
A possible plot could involve Kefla being sent to the Naruto world as part of a test by the Kais. In this world, she is intrigued by Naruto's determination. Naruto, on the other hand, is amazed by her power. They train together and learn from each other's fighting styles. This leads to a strong bond between them, and they end up protecting the Hidden Leaf Village from a powerful new threat.
One idea could be that the clone develops its own unique personality over time and forms a special bond with Naruto that is different from his relationship with others. It could start to have dreams and desires separate from its original purpose as a clone.
One plot idea could be that Naruto, using his unique ability to understand and reach out to others, tries to find a way to redeem Kaguya. He might journey through different dimensions to learn more about her past and what led her to become so power - hungry. This could involve him facing challenges in these strange dimensions and having to rely on his ninja skills as well as his compassion.
One idea could be that Naruto discovers a hidden power within himself related to Amaterasu. Maybe during a battle, he accidentally taps into it and has to learn to control this new, unexpected ability. It could be a power passed down through some ancient connection in his family.