Another theme could be redemption. If fem Itachi has done some wrong in the past, Naruto might be the one to help her find redemption. It's a way to explore the characters' moral compasses. Also, there could be a theme of discovery. As they interact, they might discover new things about themselves and the world around them.
There's also 'Fem Naruto's Adventure'. This fanfic often delves into how fem Naruto's character traits, which are a blend of Naruto's original ones but with a feminine touch, interact with Naruto himself. It could show unique storylines like how they face challenges together in a new light.
One common theme could be the struggle with their different loyalties. Itachi has her own complex backstory and Naruto has his goals for the village. Their love might be tested by these conflicting loyalties.
One common theme is the exploration of friendship. Despite their different backgrounds and personalities, they often form a strong bond in these fanfics. Another theme is redemption. Fem Itachi may have her own past actions she wants to make up for, and Naruto can be a catalyst for that.
The theme of discovery is also prevalent. Fem Naruto discovers new sides of Itachi, and he in turn discovers something different in her compared to what he expected. It's like they are exploring a whole new world together. Also, there's often the theme of sacrifice, as they may have to sacrifice things for each other in the story.
One popular theme is redemption. Many fanfics explore how Itachi, with his complex past of killing his own clan, can find redemption through his relationship with Madara. It gives a new perspective on his character.
One common theme is the overcoming of differences. Naruto and fem Itachi come from different backgrounds and have different personalities. Their marriage forces them to deal with these differences and find common ground.
Another theme is the power of love. It's often shown that their love can overcome the differences between their clans and the past grudges. They support each other in battles and in making important decisions for the ninja world. In some fanfictions, their love is what unites different factions in the shinobi world. A good example is when they use their combined influence to stop a war that was brewing due to old clan rivalries.
Love and forbidden love are common themes. Since Itachi is from the Uchiha clan and Naruto (as a female in this context) is an outcast, their relationship goes against the norms of their world.
A theme of discovery could also work well. Maybe Fem Haku discovers new aspects of herself through her interactions with Naruto. For instance, she might find a new purpose or a new side to her ninja skills. Naruto, on the other hand, could learn about different cultures or ways of life from Fem Haku. This could lead to a story full of exploration, both of themselves and of the world around them in the Naruto universe.
I'm not sure about specific 'naruto fem itachi' fanfics without slavery themes. But you can try searching on popular fanfic websites like Fanfiction.net or Archive of Our Own. Look for tags related to 'Naruto', 'fem Itachi' and exclude any tags that might be related to slavery or dark themes.