One idea could be a crossover where Bulma's technology is used in the Naruto universe. For example, she could create some new kind of ninja tools with her advanced knowledge. Maybe she helps the Hidden Leaf Village upgrade their defense systems. It would be interesting to see how the Naruto characters react to her and her inventions.
In DBZ Vegeta and Bulma fanfiction, there can be alternate universes explored. Maybe in one universe, they meet under different circumstances. For instance, instead of Vegeta coming to Earth as an enemy, he could be an ally from the start. This would completely change the dynamics of their relationship. It could lead to a more romantic and less combative start to their relationship, and the fanfiction could explore how this different beginning affects their future together.
One possible plot could be that Naruto, who has Saiyan powers in this fanfiction, somehow ends up in the Dragon Ball Z universe. He meets Bulma, and they team up. Maybe they're on a quest to find the Dragon Balls together while Naruto is also trying to figure out how to get back to his own world. Bulma could be fascinated by Naruto's unique Saiyan - ninja hybrid abilities.
It could be a story about cultural exchange. Naruto represents the ninja world with its clans, jutsu, and honor code. Bulma represents the high - tech, alien - filled world of DBZ. They start by being curious about each other's worlds. Bulma might try to study Naruto's body to understand how chakra works, and Naruto would be eager to learn about the technology in Bulma's world. As they get to know each other better, they discover that they both have a strong sense of justice and a will to protect their respective universes. So when an enemy emerges that threatens both worlds, they join forces to stop it, with Naruto using his ninjutsu and Bulma using her inventions.
Naruto's positive and determined attitude would likely inspire Bulma. When they face difficulties, Naruto would be the one to keep pushing forward, saying things like 'I'll never give up!'. Bulma would be more practical and strategic, so she'd balance out Naruto's impulsiveness. For example, if they were in a fight, Naruto would be ready to jump in head - first, but Bulma would stop him and come up with a better plan using her intelligence and knowledge of the DBZ world. They'd also have some cultural clashes. Naruto is used to a more traditional, honor - based society, while Bulma is from a world of advanced technology and different social norms.
A third fanfiction concept could be about how they prepare for the baby's arrival. Vegeta, not knowing much about Earthling baby things, has to learn. Bulma tries to teach him, and there are a lot of cultural clashes and misunderstandings at first. But as time goes on, they work together to create a perfect nursery and get ready for their new family member.
Perhaps in this fanfiction, there's a lemon - loving alien race in the DBZ world. Bulma, being the curious scientist, wants to study them, and Vegeta is dragged along. Along the way, they face challenges that force them to work together in new ways, and their relationship deepens as they navigate through this lemon - related encounter.
Well, Naruto's Saiyan nature would mean he has a strong sense of pride and a love for fighting. When he meets Bulma, she might find his fighting - loving side a bit of a nuisance at first. But as time goes on, Naruto could use his Saiyan powers to protect Bulma from various threats in the DBZ world. And Bulma would help Naruto understand the technology and culture of the DBZ universe, which is very different from his own.
Another common plot is the 'time - travel' scenario. Given the time - travel elements in DBZ, some fanfictions might send Vegeta or Bulma back in time. This can lead to interesting situations where they have to interact with their younger selves or change certain events in the past. It also gives a chance to explore their relationship in a different timeline.