As far as I know, no. The idea of 'baby bra' in relation to Vegeta and Bulma seems rather unusual. In the world of Vegeta and Bulma fanfiction, popular stories usually center around things like Vegeta's training, Bulma's inventions, and their family dynamic with Trunks. There's not much indication that a 'baby bra' fanfiction would be well - known.
There is a fanfiction called 'Baby Vegeta's Training'. In this, it details how baby Vegeta, despite his small size, still tries to train and become stronger. It's interesting as it gives insights into his character and his unwavering determination to be the best, even as a baby.
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.
One possible plot could be Vegeta training with baby Bulla. He could be teaching her the basics of combat in a gentle yet firm way. For example, showing her how to throw a proper punch or dodge an attack. He might also tell her stories about their Saiyan heritage during breaks in the training.
The theme of Saiyan heritage also frequently appears. Since both are Saiyans, fanfictions may explore how their Saiyan nature affects their relationship. For instance, their shared instinct for battle and their connection to Saiyan traditions can be central to the plot.
The baby might be really competitive, getting that from both of them. Vegeta is always striving to be the best, and Goku loves a good fight. But it could also be really kind - Goku's a good - hearted guy, so that would rub off. Maybe a bit of a goofball too, like Goku.
One potential theme could be family. Vegeta's relationship with his son is explored, showing how a Saiyan warrior like him can adapt to fatherhood. Another theme might be growth, as Baby Trunks learns from Vegeta and Vegeta also grows as a person through this new connection.
Well, it could be that Vegeta, upon meeting Baby Trunks, realizes the importance of family in a new way. He might start to see the future differently, knowing that he has a son to protect and guide. There could also be some cute moments where Baby Trunks tries to imitate Vegeta's tough guy expressions, which would be quite endearing.
In this fanfiction, the baby might be a key to uniting different factions in the Dragon Ball universe. Since Vegeta has his Saiyan heritage and Bulma is an Earthling, their baby could symbolize a new era of peace and cooperation. The story could show how the baby grows up being adored by all the Z - fighters. Vegeta would be protective and train the baby in secret, while Bulma would be showing off the baby's cute side to her friends. There could also be some comical moments when the baby's Saiyan appetite clashes with Bulma's attempts to feed it a balanced diet.
There could be a rogue Saiyan who has different ideals from Vegeta. This Saiyan might think that the baby should be raised in a more traditional, warrior - like way and try to take the baby from Bulma and Vegeta. Or, an evil scientist who wants to experiment on the baby's unique Saiyan - human DNA could be the main antagonist, creating all kinds of challenges for Vegeta and Bulma to protect their child.