Well, in some fanfics, there's a plotline where Hinata loses her memory and Naruto has to make her fall in love with him all over again. It's a classic but still very engaging. There are also stories where they are arranged to be married for political reasons at first, but then they actually fall in love for real during the process. And a really unique one is when Hinata becomes a super powerful ninja overnight and Naruto has to deal with his feelings of being a bit overshadowed while also being proud of her.
One interesting plotline could be Hinata becoming a powerful ninja in her own right and protecting Naruto instead of the other way around. For example, she could master a new and unique jutsu that saves Naruto from a powerful enemy.
In some Naruto and Hinata mate fanfictions, a great plotline is their parenting journey. They have to raise their children in a world full of challenges. Maybe their kids inherit unique abilities that draw unwanted attention. Naruto and Hinata have to teach their children the values of the Hidden Leaf, and at the same time, protect them from those who might want to use their powers for evil. This creates a lot of drama and also shows their growth as parents and as a couple.
A possible plotline is that the symbiote has its own agenda. It might try to influence Naruto in ways that are not good for the village. Hinata then has to figure out a way to separate the symbiote from Naruto without harming him. She could use her Byakugan to study the symbiote's connection to Naruto.
One interesting plotline could be where Hinata gets a new power and Naruto has to learn to work with her in a different way. For example, if Hinata got a power related to time - manipulation, it would create a whole new dynamic in their relationship and adventures.
One interesting plotline could be Naruto slowly realizing his feelings for Hinata during a dangerous mission. Maybe they get separated from the group, and in that time of solitude and relying on each other, Naruto starts to see Hinata in a new light.
One interesting plotline could be Hinata secretly training harder to impress Naruto. She might be doing it on her own without anyone knowing, and then one day she surprises Naruto with her new skills.
One possible plotline could be a story where Naruto has to choose between two versions of Hinata, the original Hinata and a version from an alternate RTN (Road to Ninja) universe. Maybe in this fanfiction, the different Hinatas have unique abilities or personalities that make Naruto's choice more difficult.
One possible plotline could be Naruto and Hinata using their newfound god - like powers to protect the Hidden Leaf from a powerful, otherworldly threat. They could travel to different dimensions to gather allies or resources. Another could be them having to deal with the moral implications of being gods, like how much they should interfere in the lives of mortals.
A plotline that often appears is Naruto and Hinata being neighbors in a modern apartment complex. Naruto is always noisy and active, which at first annoys Hinata. But as time goes by, she starts to see his kind heart. For instance, when Hinata loses her cat, Naruto spends all day looking for it. This event starts a friendship that slowly turns into love as they get to know each other better through shared experiences in their neighborhood.
A really interesting plotline might be where Hinata's aggression is a result of some new power she has obtained. This power makes her more confident and bold. She then uses this new - found aggression to help Naruto in his quest to bring peace to the ninja world. For example, she might be the first to volunteer for dangerous undercover missions, which Naruto is initially hesitant about, but she convinces him with her determination.