One plotline could be that Pansy Parkinson gets pregnant unexpectedly and has to deal with the social implications within Hogwarts. Maybe she has to face the judgment of her peers and figure out how to continue her studies while pregnant.
Perhaps Pansy Parkinson is pregnant as a result of a dark magic experiment gone wrong. She then has to find a way to reverse the situation or deal with the consequences. This could lead to her seeking help from unlikely allies within Hogwarts, like some of the more reclusive professors or students from different houses. She might also have to face the wrath of those who were involved in the dark magic experiment in the first place.
One possible plotline could be Ginny trying to hide her pregnancy from her friends and family at Hogwarts. She might be worried about the reactions and how it would affect her studies and her standing in the wizarding world. Another could be that she decides to confide in a few close friends, like Hermione, who then help her navigate the difficult situation while also dealing with the regular Hogwarts adventures. Maybe there's a mystery surrounding who the father is, adding an element of intrigue to the story.
One possible plotline could be that Pansy is in a secret relationship with someone at Hogwarts, and the pregnancy is a huge shock to her and her partner. They then have to deal with the consequences, like how to hide it from other students and teachers, and what their future might hold.
One possible plotline could be Ginny trying to hide her pregnancy from her friends and teachers at Hogwarts while also dealing with the physical and emotional changes. Another could be the father of the baby, whoever it may be, stepping up or shirking responsibility. Or perhaps Ginny seeking help from a particular magical creature or spell to deal with the situation in a way unique to the wizarding world.
I'm not sure there are a lot of specific 'Parkinson pregnant' Hogwarts fanfictions that are widely known. You could try searching on some major fanfiction platforms like Fanfiction.net or Archive of Our Own. Just be aware that the quality and content can vary greatly.
One possible plotline could be Rangiku dealing with the challenges of pregnancy while still being involved in her usual activities in the story's setting. For example, if it's in a fantasy or action - based world, she might have to balance her duties and the physical changes she's going through.
A plotline might involve Snape being removed unjustly. His allies or some students who knew his true nature might try to fight for his reinstatement. There could also be a story where Snape's removal causes a power vacuum in Hogwarts, and different factions start vying for control of certain aspects of the school. It could also lead to a discovery of secrets that Snape was protecting while he was at Hogwarts.
One possible plotline could be about the challenges Reshiram faces during pregnancy. For example, how it adjusts to its changing body and powers. Another could be the reactions of other Pokémon characters in the story, whether they are supportive or not.
One possible plotline could be the challenges she faces during her pregnancy. Maybe she has to deal with the reactions of her friends and family within the fandom's world. Another could be how she manages her normal duties or adventures while being pregnant.
One possible plotline could be how Nami and the other Straw Hat crew members react to her pregnancy. Maybe they would be overly protective or excited. Another could be about Nami dealing with the physical and emotional changes during pregnancy while still being part of the crew's adventures.
One possible plotline could be that Tinkerbell's pregnancy is a magical accident. Maybe she was exposed to some strange magic that caused this unexpected situation. Another could be that she is in love with a fairy or a character from the Peter Pan universe and they are starting a family together.