One interesting plotline could be where Vegeta and Bulma meet in a completely different social context in the alternate universe. For example, if Vegeta was a scientist like Bulma instead of a Saiyan warrior. They could collaborate on some super - advanced technology project and during the process, their relationship could develop in a new and unique way.
In some fanfictions, the alternate universe might have different power dynamics. Maybe in this universe, Bulma has some hidden power and Vegeta is initially intrigued by it. Their relationship could start from a place of mutual curiosity about each other's abilities rather than the more traditional attraction based on their original story roles.
Another character could be Dr. Briefs, Bulma's father. In the alternate universe, he might have a more prominent role in bringing Vegeta and Bulma together. For example, he could be the one who arranges for Vegeta to work on a project with Bulma, which starts their relationship on a more professional note that gradually turns into something more personal.
Well, a common plotline is the development of their relationship from a rather tense and unexpected start. Vegeta, being a Saiyan, has a different mindset compared to Bulma. In the fanfiction, their love might grow as they face challenges together, like threats to Earth. And perhaps there are some comical moments where Vegeta's Saiyan pride clashes with Bulma's feisty personality, which adds to the charm of the story.
Perhaps a plotline where Vegeta's feral nature actually gives him an edge in protecting Bulma and the Earth. His wild instincts make him more perceptive to threats, and he and Bulma have to learn to communicate in a new way because of it. They might have to develop a sort of code or understanding that is unique to their relationship, and this could lead to some really interesting adventures and character development for both of them.
One possible plotline could be Vegeta and Bulma going on an adventure together to find a new power source for Capsule Corp. Another could be them dealing with a new enemy that specifically targets their relationship. And there might be a plot where they have to travel back in time and face challenges that test their love for each other.
One possible plotline could be Vegeta struggling with his inner demons while trying to protect Bulma from new threats in a darker, more dangerous world. For example, a powerful new villain emerges and Vegeta has to use his Saiyan powers in ways he never has before, all while dealing with his complex relationship with Bulma.
One interesting plotline could be Vegeta trying to understand human emotions while being in a relationship with Bulma. For example, he might struggle with expressing his love in a way that Bulma can understand. Another could be them facing challenges together, like threats from other villains that target their relationship or family. And there could also be a plotline where Vegeta has to adapt to Earth's culture more deeply because of his relationship with Bulma, which includes things like participating in Earth's holidays or social events.
One possible plotline could be that when Vegeta first meets Bulma, he is initially dismissive of her because she is a weak Earthling in his eyes. But as time goes by, he starts to notice her intelligence and tenacity, which intrigues him. For example, she might be the one to figure out how to repair his spaceship, and he begins to see her in a new light.
One interesting plotline could be where the Starks never lose their power in the North. Instead of Ned Stark's execution, he manages to outwit his enemies and unites the North even more firmly against the Lannisters. This would change the entire power dynamic in Westeros as the North would be a much stronger force from the start.
One interesting plotline could be Naruto arriving in an alternate universe where the Akatsuki are the heroes. He has to figure out how to navigate this new world where his former enemies are now revered.
One interesting plot could be Vegeta trying to understand human emotions better because of his relationship with Bulma. He might struggle with expressing his love in a more 'human' way, which could lead to some really sweet and comical moments.