Some fanfictions might explore a what - if scenario where Bulma and Chichi were switched at birth. This would completely change their lives and personalities as they grow up in different environments. Bulma would be trained in martial arts by Goku's family, and Chichi would be exposed to science and technology at Capsule Corp. It would be interesting to see how they adapt to these new situations and how their relationships with the other characters change.
One popular storyline could be Bulma and Chichi teaming up for a scientific - martial arts project. Since Bulma is a genius inventor and Chichi is a strong martial artist, they might combine their skills to create something extraordinary, like a device that can enhance martial arts abilities using science. Another could be a story where they go on an adventure together to a new planet or a hidden realm on Earth. There, they face various challenges and learn more about each other's strengths and weaknesses.
A common plot might involve Bulma and Chichi getting into a friendly competition. Maybe they bet on who can train their sons better in a particular aspect, like speed or strength. This could lead to some hilarious and heartwarming moments as they both try different training methods and learn from each other in the process. Or perhaps they are both invited to a grand intergalactic event and have to navigate the complex social and political situations there together.