One interesting plotline could be Bulma's adventures in different dimensions. She could be exploring new worlds, meeting alternate versions of herself and her friends, and having to use her intelligence to solve problems specific to those dimensions.
One possible plotline could be a misunderstanding that leads to a rift between Bulma and Goku in their friendship. For example, Goku might accidentally break one of Bulma's important inventions, and she misinterprets it as him being careless on purpose. This could then lead to a series of events where they have to work through their differences and reconcile.
A possible plotline could be that Goku and Bulma's marriage leads to a new era of peace in the Dragon Ball universe. With Goku's strength and Bulma's intelligence, they could start initiatives to better the lives of all the races in the universe. They might also have children with unique powers that are a combination of Saiyan and human genetics, and the story could follow their growth and development.
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.
Perhaps a plot where they have to deal with a mischievous alien who has a strange fascination with their daily lives. They could end up using their unique skills, Chichi's martial arts and Bulma's intelligence, to outwit the alien.
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.
In a fanfic, Future Gohan and Bulma could embark on a journey to find the Dragon Balls. Bulma hopes to use the Dragon Balls to wish for the destruction of the Androids. Along the way, they face many challenges and obstacles. Gohan protects Bulma from various threats, and in the process, they learn more about each other's strengths and weaknesses. This could also be a story of self - discovery for both of them, as Gohan tries to come to terms with his role as the last hope for the world and Bulma tries to accept that she may not be able to save everyone with her inventions.
Love and relationships are also common themes. Bulma might find love within the context of her new royal status. This could be a relationship with an existing character like Vegeta, or a new character introduced in the fanfic. There's also the theme of conflict. She could face opposition from other royals or from those who don't want her to take the throne. It creates drama and tension in the story.
One possible plotline is that they are on the rooftop to escape the chaos of the city below. They find peace and quiet there, and it becomes their special place. They might start reminiscing about their adventures together and how far they've come as a couple.
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.
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.