Well, it could be that Cell has some sort of malfunction that only Bulma can fix. He travels to find her, and when they meet, Bulma is hesitant at first. But as she starts to understand Cell's situation, she decides to help him. This then leads to a series of adventures where they have to face other threats together while Bulma continues to work on Cell's issues.
Perhaps in this fanfiction, Cell somehow ends up in Bulma's laboratory. She initially panics but then realizes she can study Cell. Cell, on the other hand, is interested in Bulma's scientific knowledge and they start a strange alliance that eventually turns into an unexpected friendship.
Maybe in the fanfiction, Future Bulma meets a younger Vegeta who has been sent to the future by some time - related accident. At first, Vegeta is confused and angry, but Bulma's intelligence and determination start to intrigue him. They could have a series of adventures together, with Bulma trying to help Vegeta adapt to the future while also using his strength to protect what's left of their world.
There's a possibility that an evil scientist from another planet could be the main antagonist. This scientist wants to use Bulma's knowledge and Cell's power for his own evil experiments. So he tries to break up their partnership and capture them both for his own purposes. He sends his minions after them and creates various obstacles for Cell and Bulma to overcome.
Well, in this fanfiction, Goku and Bulma might go on an adventure together. They could explore new planets or search for the Dragon Balls in a different way than in the original story.
Vegeta could become more empathetic. Meeting Future Bulma might expose him to different perspectives and make him understand the consequences of his actions better.
In this fanfiction, perhaps King Vegeta would be initially suspicious of Bulma. He's from a warrior race and she's an Earthling scientist. He might be intrigued by her technology though, like her capsule corps inventions.
Well, maybe Vegeta would be shocked to see Future Bulma at first. He might be confused about how she got there and what the future holds for them. Then they could start to share stories about what has happened in their respective timelines.
In such a fanfiction, one possibility is that Vegeta and Bulma could have an adventure together. Maybe they explore a new planet and face some unknown threats. Vegeta's combat skills combined with Bulma's intelligence would make them a great team.
One possible plot could be centered around how Vegeta adjusts to the idea of becoming a father. He's a proud Saiyan warrior, so he might initially struggle with the more nurturing aspects. For example, he could be shown trying to train while also being worried about Bulma's well - being during her pregnancy. Maybe he starts to research Saiyan pregnancies to make sure everything is going as it should.
One possible plot could be that Bulma accidentally takes an overdose of some experimental pills she was working on in her lab. Her friends, like Goku and Vegeta, notice her strange behavior and try to figure out what's wrong. They search her lab for clues and find the empty pill bottle. Then they have to race against time to find an antidote or a way to reverse the effects of the overdose.
The story might center around a new threat to the Earth that only their combined efforts can defeat. Vegeta uses his fighting skills and Bulma uses her intelligence to create new gadgets or find weaknesses in the enemy. Along the way, they reaffirm their love for each other and strengthen their family unit.