One idea could be a story about Bulma's inventions and how Baby Trunks gets involved in her experiments. For example, he could accidentally activate a device that sends them on an adventure through time or to a different dimension.
One idea could be a story where Bulma invents a new device to help Baby Trunks train more effectively. For example, she creates a gravity simulator that allows him to train in conditions similar to different planets.
A great plot twist could be that Baby Trunks is actually from an alternate future where things are very different. This would change the whole dynamic of how Bulma relates to him. Maybe in this future, Bulma didn't survive, and now he has come back to change the past.
In a fanfiction, there could be a story where an enemy specifically targets Baby Trunks because of his Saiyan heritage. Bulma steps up as his protector, using her inventions to fend off the attacks. Along the way, they develop a stronger bond as they face this common threat together. Bulma also discovers new aspects of her own strength and courage in protecting Baby Trunks.
Their relationships are often shown as loving yet complex. Vegeta, who was once a cold - hearted warrior, has a soft spot for his family. He is protective of Bulma and Baby Trunks. Bulma is the brains of the family, and she manages to keep Vegeta in check. Baby Trunks is the source of joy and also a reason for Vegeta to strive to be a better person.
Fanfiction can explore their relationship by looking at their cultural differences. Vegeta is a Saiyan from a warrior race, while Bulma is a human scientist. Baby Trunks is a mix of both. So, a story could be about how they teach Trunks about his dual heritage, like Vegeta teaching him about Saiyan pride and Bulma teaching him about human values like kindness and curiosity.
A fanfiction could focus on a day in the life of the family. Bulma could be working on some new invention in her lab, Vegeta is training hard outside, and Baby Trunks is getting into all sorts of cute mischief. Then, something unexpected like a small alien invasion occurs near their home, and they all have to work together to deal with it.
Some common themes could be family bonds. Since Bulma is Trunks' mother, stories might explore their relationship within the family dynamic. Another theme could be adventure. Given their association with the Dragon Ball universe which is full of action and adventure, fanfics might have them going on quests together. Also, character development is a likely theme, showing how Trunks grows up under Bulma's influence or how Bulma matures as a mother over time.
First, think about the relationship between them. You could start with a scenario like Trunks coming home from school with a problem and Bulma using her wisdom to solve it. Then, build on their personalities. Bulma is smart and sassy, and Trunks is brave and determined. Include these traits in your story.
To make a Bulma and Trunks fanfic stand out, writers can focus on unique character perspectives. For example, showing Trunks' view of Bulma's scientific work from a child's perspective when he was young, and then as he grows older. Another way is to create original plotlines that haven't been overdone. Instead of the typical adventure story, they could write a story about a day in their lives where they have to deal with normal, everyday problems in a world full of super - powered beings. Also, using vivid and detailed descriptions of the Dragon Ball world, especially Bulma's lab and the technology in it, can make the fanfic more engaging.