A possible plot could be that Bella's death was part of some sort of prophecy or foreshadowed in some way throughout the fanfic. The fanfic could explore the reactions of different characters who had different relationships with Bella. For example, her friends might be in shock and disbelief, while her family might be more focused on taking care of the practical matters like the funeral arrangements and the baby's future.
One possible plot could be that the story focuses on the grief of those left behind, like her partner. They might struggle with the sudden loss and have to figure out how to take care of the newborn without her. Another plot could involve the backstory leading to her death, perhaps there were complications during the birth that no one saw coming. And it could also show the impact on the community around her, how they come together to support the family in this difficult time.
One possible scenario could be that there were complications during the birth that couldn't be overcome. Maybe there was excessive bleeding or an undetected health issue that led to her death.
Her partner could be a main character. They would be deeply affected by her death and would likely have to take on a lot of responsibilities, especially in terms of raising the baby. The baby itself could also be considered a main character in a sense, as the story could follow its growth and development in the absence of its mother.
One possible plot could be that the story focuses on the emotional turmoil of those around Sakura. Her friends and family might be in shock and disbelief as they were expecting a joyous birth but instead are faced with her death. They could struggle with guilt, thinking if there was something they could have done to prevent it.
Perhaps the Cullen family has to deal with the shockwaves of Bella's death. They may face challenges from the vampire community as Renesmee is a unique being. Some vampires might see her as a threat or an abomination. The family would then have to protect Renesmee at all costs while also mourning Bella.
The baby, of course. Growing up without a mother would be a huge part of the story. The father would also be deeply affected, having to raise the child alone and deal with the grief of losing his partner.
Well, it could be about the challenges Bella faces during the birth, like the pain and fear. Maybe it also shows the support she gets from her family or friends around her.
One possible plot could be Sasuke being away on a mission when Sakura goes into labor. She has to rely on her friends like Ino and Tsunade to help her through the difficult process. When Sasuke finally returns, he is filled with joy and a new sense of responsibility towards his family.
Perhaps in the 'naruto dies narusaku fanfic', Naruto sacrifices himself to save Sakura from a powerful enemy. Sakura, in her despair, starts to discover new aspects of Naruto she never fully realized when he was alive. She could then start a journey to find a way to bring him back, encountering many challenges along the way and meeting old friends and foes who either help or hinder her.
Maybe in the fanfic, Aunt May's death is the catalyst for Peter to take on a more serious and darker approach to fighting crime. He could start to question his no - killing rule more severely. For example, he might face a villain who was directly or indirectly responsible for Aunt May's death and be on the verge of crossing that line.
One possible plot could be that Ruby is facing an overwhelmingly powerful enemy alone. Despite her best efforts, she is mortally wounded in the battle and dies heroically. Another could be that she sacrifices herself to save her friends from a deadly trap or a powerful Grimm attack.