In some fanfics, their sibling relationship could be explored through flashbacks. For example, showing how they were separated as children due to some intergalactic event. Then, in the present, they are reunited and have to catch up on all the years they missed. This could involve them learning about each other's cultures and dealing with the differences between being a Martian and a shape - shifter.
A key element would be the discovery of their relationship. It could be a shock to both of them and the reactions would be interesting to explore. Another element is how they interact with their shared friends and teammates. Do they keep it a secret or are they open about it? Also, their different powers could play a role. Maybe they combine their powers in unique ways to solve problems because of their new - found bond.
A theme that sometimes pops up is teamwork. Since they are part of a team in the original series, fanfics may focus on how they work together in different scenarios, highlighting their individual strengths and how they complement each other. Also, the theme of acceptance can be seen. For example, Beast Boy might have to accept Miss Martian's different cultural background or powers, and vice versa, which can create interesting storylines in fanfics.
You can start by looking on fanfiction platforms like Archive of Our Own (AO3). It has a large collection of fanfics for various fandoms, including Beast Boy and Miss Martian. Another option is FanFiction.net. Just search for the relevant tags and you'll likely find some interesting stories.
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.
One great fanfic with this theme could be 'Raven's Hidden Heart'. In it, the author beautifully depicts Raven's journey as she discovers her feelings for Beast Boy. It starts with small, almost unnoticed moments between them during team missions. The story gradually builds up the tension and the development of their relationship is very natural, showing Raven's internal struggle with her emotions.
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.
I really like 'Terra's Redemption'. In this fanfic, Terra gets a second chance at life and tries to make things right with Beast Boy. It has a lot of heart - felt moments and shows how their relationship can evolve over time. There are also some really cool action scenes that tie into the story. Overall, it's a great read if you're into Terra x Beast Boy fanfics.
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.
One great 'Starfire x Beast Boy fanfic' is 'A Different Kind of Bond'. It shows their relationship developing in a really unique way. The story has a lot of heartwarming moments as they learn more about each other.
Perhaps it could be a story where Naruto is accidentally transported to Miss Martian's universe. He is confused at first but quickly adapts. Miss Martian helps him understand the new world and in return, Naruto teaches her some of his ninja techniques. Their friendship grows as they face challenges together, like dealing with villains who want to use Naruto's power for evil in this new universe.