One plot idea could be that Raven discovers she's pregnant and is initially in denial. She tries to hide it from the rest of the Teen Titans, especially Beast Boy, because she's afraid of how he'll react. Another could be a more comical take where Beast Boy accidentally finds out before Raven has a chance to tell him, and he goes into over - protective mode immediately. Maybe he starts reading every pregnancy book he can find and trying to cook special healthy meals for Raven, much to her annoyance at first.
Perhaps in the fanfiction, the pregnancy could be a result of some sort of magical or alien interference. This would add an extra layer of mystery and adventure. They would then have to not only deal with the pregnancy itself but also figure out what caused it and if there are any hidden dangers or powers associated with the baby due to this strange origin.
One idea could be that they are hurt during a battle with a powerful new villain. Maybe they underestimate the enemy's strength and end up with physical injuries. This could lead to them having to rely on each other more for support and also force them to confront their own weaknesses.
A plot could involve a new villain who targets their relationship. This villain could create illusions or situations that make Raven and Beast Boy question their feelings for each other. But as they fight through these false obstacles, they actually end up realizing that their love is stronger than they thought. For instance, the villain might make Raven think that Beast Boy is only interested in her because of her powers, but Beast Boy then shows his true self and his genuine love for her beyond any powers or abilities.
Maybe a plot where their relationship changes and develops because of the pregnancy. They could start off as just friends or comrades and then become closer as they navigate the pregnancy together. There could be a lot of emotional growth and self - discovery for both characters.
One idea could be that Raven discovers she's pregnant and is initially scared because of her unique powers. Dexter, being the scientific mind, tries to find a way to ensure the baby will be healthy. He starts researching how Raven's powers might affect the pregnancy.
One plot idea could be that they accidentally get pregnant due to some sort of alien or magical mishap. For example, a strange alien device that was meant for something else malfunctioned and caused Starfire to become pregnant. Another idea is that they decide to have a baby as a way to bring their two different cultures (Tamaranian and Earth) closer together. They could face challenges from their friends and family who might not be ready for them to become parents at such a young age.
One idea could be a story where Raven, Beast Boy and Terra go on a quest together to save their world from a new, powerful enemy. Along the way, Raven and Beast Boy's relationship could be explored more deeply, while Terra struggles with her own powers and how she fits in with the group.
A great fanfiction concept could be a time - travel story. They accidentally get sent back in time and have to find a way to get back to their own era. Along the way, they meet younger versions of themselves or other important characters. Beast Boy might be excited to see how things were in the past, Raven could be more cautious, and Starfire would be curious about the different cultures and technologies.
One idea could be that the Beast is initially shocked but then becomes extremely protective of Casey during her pregnancy. He might start learning about human pregnancy and all the care that is needed, like building a safe and comfortable place for Casey to rest.
One plot idea could be that Raven discovers she's pregnant in a world full of chaos and has to find a safe place for her unborn child. Maybe she teams up with some unexpected allies who help her on this journey.