Maybe Bulma is too busy with her scientific research and family matters to be interested in fanfic about Vegeta. She has a lot on her plate, from taking care of Trunks to working on new inventions.
In many fanfictions, Vegeta starts as an outsider. He's a Saiyan in a world full of mages. His initial development is about adapting. He has to learn the rules of the Fairy Tail world. For instance, he might not understand the concept of magic guilds at first. As he spends more time there, he becomes more open - minded. He starts to see the value in the friendships and teamwork that are so important in Fairy Tail.
You can try some popular fanfic websites like FanFiction.net or Archive of Our Own. Use the search filters to specifically look for Bulma - centered stories and exclude any tags related to Vegeta.
One way to find secure Bulma - Vegeta fanfics is to follow some trusted fanfic authors. If you know an author who has written great Dragon Ball - related stories in the past without any security problems like malware or inappropriate content, chances are their other works about Bulma and Vegeta will be good too. You can often find these authors by looking at the 'favorites' or 'followed' lists of other Dragon Ball fans on fanfic platforms.
One of the top stories could be about Vegeta's intense battles against powerful foes. His fight against Goku is always a significant story. Vegeta constantly tries to prove himself as the strongest, and these battles showcase his growth and determination.
If Vegeta was a girl, it might change the dynamics within the Dragon Ball universe. Her interactions with other characters could be very different, and her power might be perceived differently too.
One challenge could be protecting the baby from their enemies. Vegeta has made many foes over the years, and they might target the baby. Also, Vegeta's Saiyan nature might make him push the baby too hard in training, while Bulma wants a more relaxed approach. This difference in parenting styles could cause some friction between them.
The relationship could develop in a more emotional way. Maybe Trunks gets injured badly in a fight, and Vegeta realizes how much he cares for his son. He then becomes more protective and affectionate towards Trunks. On the other hand, Trunks could also start to understand his father better, seeing that Vegeta's tough love is actually a way of showing his love and concern. This new understanding could lead to a more harmonious and loving relationship between them.
Vegeta would likely still be his proud and strong - willed self, but with a newfound tenderness towards Bulma. He might be a bit more protective and less quick to anger. Bulma, on the other hand, would be her intelligent and sassy self, always ready to challenge Vegeta in a playful way.
In a fanfic, Naruto might power up by having a spiritual awakening. He could connect with the spirits of past Hokages in a deeper way, gaining their knowledge and some of their power. This could enhance his existing jutsu and give him new abilities. Vegeta could power up if he were to face a near - death experience against Naruto. This could trigger a hidden potential within him, like a new type of Super Saiyan form that has unique abilities. He could also fuse with another Saiyan (if there were another Saiyan available in the fanfic's scenario) to create an even more powerful being.