One possible plot could be that they face challenges in protecting their unborn child from enemies who might want to use the baby's powers for evil. Since both are Martians, their child would likely have unique and powerful abilities that could attract unwanted attention.
Perhaps the fanfic could explore the relationship between Miss Martian and the father of the child. It could show how they support each other through the pregnancy, and also how their relationship evolves. There might be moments of joy, worry, and discovery as they prepare to become parents.
Obviously, Miss Martian herself is the central character. Her friends and teammates from the superhero group she belongs to could also be involved. For example, Superboy might play a role as a friend or protector. He could be there to support her during difficult times or help keep her and the baby safe from any threats.
One common theme is the exploration of her relationships. For example, how her pregnancy might affect her relationship with her teammates or love interests. It could show a more vulnerable side of her character.
You can try looking on fanfiction platforms like Archive of Our Own (AO3). There are often a wide variety of fanfictions related to different characters and scenarios, including ones about Miss Martian being pregnant. Just use the search function on the site and type in relevant keywords.
Friendship and teamwork are also common themes. Since they are from different universes, they have to work together. They learn to trust each other and overcome their differences. In many fanfics, they form a strong bond that helps them face various challenges, whether it's a powerful villain or a difficult situation in a strange new world.
In some fanfics, Miss Martian might teach Naruto about her alien culture and technology. This could be really fascinating as Naruto is always eager to learn new things. He could then use some of this knowledge to improve his own village. It's also interesting to see how the two characters from very different universes interact with each other's friends and allies.
It could show how they become more protective of each other. With the pregnancy, they might be more cautious in their actions, both in and out of their superhero personas. For example, Martian Manhunter might be more vigilant in protecting Miss Martian from any potential threats.
Well, in fanfics, Miss Martian and Superboy could have a very complex relationship. They are both powerful characters with different personalities. Their relationship could be based on mutual respect for their powers and the challenges they face. Maybe they start as friends who train together and gradually develop a deeper bond as they understand each other's backgrounds better. For example, Miss Martian's alien nature and Superboy's clone - origin could be points of connection as they both feel a bit out of place in the human world sometimes.