One common theme could be misunderstandings between Naruto and Hinata. Maybe Naruto accidentally says something hurtful without realizing Hinata's true feelings. Another theme might be Naruto being influenced by some external factor, like a powerful enemy's mind - control, which makes him act in a way that harms Hinata.
One common theme could be betrayal. Since Hinata is hurting Naruto, it gives a sense of betrayal as they are usually seen as having a positive relationship. Another theme might be redemption. Maybe after Hinata hurts Naruto, she realizes her mistake and tries to make it up to him. It could also explore the theme of sacrifice. As I mentioned before, if Hinata is hurting Naruto to save someone else, it's a form of sacrifice.
One common plotline could be Hinata choosing someone else over Naruto, which deeply wounds him. Another might be Hinata lying to Naruto about something important, causing him emotional distress. There could also be a plot where Hinata physically harms Naruto in a moment of being controlled or influenced by some external force.
One common theme is love and romance. Since their relationship is a significant part of the Naruto series, many fanfictions expand on how they fall in love and deal with the challenges that come with it.
Another common theme is the exploration of their powers in relation to each other. For example, how Hinata's Byakugan and Naruto's Nine - Tails power could be combined in some way during battles or training. Also, the theme of family and legacy, especially as they start their own family, is quite popular in these fanfictions.
One common theme is love and relationship development. Since their relationship in the original series is a significant part of the story, fanfictions often expand on it. They show how their feelings for each other grow over time, from Hinata's initial shy admiration to a deep, mutual love.
The theme of loyalty is quite common too. Hinata has always been loyal to Naruto, and Naruto is loyal to his friends and the village. In fanfictions, this loyalty can be tested in different situations. For instance, when the village is in danger, how do they stay true to each other and their values? And there are also themes related to the ninja world, like exploring new jutsus together or uncovering secrets about the history of the Hidden Leaf Village.
Perhaps in the story, there is a competition for a rare ninja item or a special mission opportunity. Kiba, being very competitive, sees Hinata as a threat. He tries to intimidate her by making fun of her skills in a very mean way. Hinata, who is already a bit shy and self - conscious, is deeply hurt by Kiba's actions. Naruto, on the other hand, witnesses this and stands up for Hinata, which then starts a whole new plot development in the fanfiction.
Another theme is unrequited friendship. Naruto sees Sasuke as his closest friend, but Sasuke's actions sometimes make Naruto feel like that friendship is not mutual, leading to hurt feelings. It's often about Naruto's struggle to hold on to that friendship in the face of Sasuke's coldness.
One common theme could be Naruto making a mistake that physically or emotionally hurts Kakashi. For example, he might accidentally use a new jutsu that backfires and injures Kakashi. Another theme could be Naruto's actions causing Kakashi to feel betrayed, like if Naruto were to side with an enemy temporarily.
One common theme is Hinata's growth. She goes from being a shy and somewhat underestimated character to a powerful force. Another theme is her relationship with Naruto in the context of her new - found strength. Sometimes it's about how Naruto starts to see her in a new light.