One popular plot idea could be Ahsoka having to balance her pregnancy with her duties in the Jedi world. Maybe she has to keep it a secret at first because of the strict Jedi code. Another could be the father of the child being a mysterious figure, leading to a search for his identity throughout the story. And perhaps the pregnancy gives her new insights and powers, like a deeper connection to the Force.
A more emotional plot idea could be that Nami gets pregnant by someone she loves deeply, but that person is lost or in danger. She then has to go through the pregnancy alone, with the support of the Straw Hat crew. The story could focus on her growth as she becomes a mother - to - be and how she overcomes the challenges without her partner.
Well, a plot could involve Natsu and Lucy trying to keep the pregnancy a secret at first. They don't want to cause a stir in the guild right away. As the pregnancy progresses, they start to realize they need to prepare. Natsu tries to earn extra money by taking on dangerous jobs, which Lucy doesn't like. Meanwhile, the baby could have some sort of special magic that starts to show even before it's born, attracting the wrong kind of attention from dark mages.
One idea could be that they reunite after a long time apart. Ash has become a more mature trainer and Serena has achieved her dreams too. They realize their feelings for each other have deepened. One passionate encounter leads to Serena getting pregnant. Then they have to deal with how their families and friends will react, and also how they will balance their future goals with raising a child.
A plot could revolve around how Rex and Ahsoka deal with the reactions of their friends and former comrades. Some might be supportive, while others might be shocked or even disapproving. Their journey could be about finding acceptance not only for their relationship but also for the new life they are bringing into the world. They could also face threats from those who see their relationship as a threat to the established order.
Well, perhaps in the fanfiction, Godzilla's pregnancy is part of a prophecy. The story could then revolve around the search for the meaning of this prophecy. Scientists or other characters might try to study Godzilla during her pregnancy to understand how it could impact the world. And there could be a race against time to either protect Godzilla and the unborn or to prevent a potential disaster that the pregnancy might bring.
In a different take, their pregnancy could be part of a prophecy. The galaxy is in a state of unrest, and their unborn child is seen as a potential savior or a bringer of great change. Ezra and Ahsoka then have to protect the pregnancy from those who would either use the child for their own gain or try to prevent the prophecy from coming to pass. They travel across the galaxy seeking safe havens and allies to ensure the safety of their unborn baby.
Perhaps in the fanfiction, Nathan and Max are in a world where they are part of a special group or have unique powers. Their pregnancy could be a result of some kind of magical or extraordinary event. They then have to deal with not only the pregnancy but also protecting their unborn child from those who might want to use its potential powers.
In a fanfiction where Regina gets Emma pregnant, a plot could involve Regina being in denial at first. She's always been in control and this unexpected pregnancy shakes her world. Emma, though, is determined to make it work. They could start exploring different parenting styles from their own upbringings. Another plot might be that there are outside forces trying to manipulate the pregnancy for their own gain. This could lead to Regina and Emma having to fight to protect their unborn child. Also, the story could focus on how their relationship evolves during the pregnancy. They might start off as just friends or reluctant allies and grow into a loving couple as they prepare for the baby.
Well, perhaps Apollo and Percy are in a secret relationship. The pregnancy could be a result of a magical experiment gone wrong. They then have to hide it from the other demigods and gods. Percy might be worried about how his friends will react, while Apollo is more concerned with the divine implications. They could go on a journey to find a way to reverse it, but along the way, they start to bond more with the unborn child.
One idea could be that it's a magical accident due to a misfired spell. Maybe Harry was trying to help someone with a fertility spell and it backfired on him. Another could be that it's part of some ancient prophecy where a male must carry a child for a great purpose. And perhaps there's a new type of magic that allows male pregnancy and Harry is the first to experience it in the wizarding world.