Perhaps a fanfic could be about an alternate universe where Yamcha was always more confident in his relationship with Bulma. In this universe, they go on adventures together, exploring new planets and having to rely on each other. This would strengthen their bond and make for an exciting story about their relationship.
One idea could be that Kakarot and Bulma go on an adventure together to find a new power source for Capsule Corp. They face various challenges along the way and their relationship deepens as they rely on each other for survival.
One idea could be that Frieza, in a strange turn of events, spares Yamcha during a battle and then gradually becomes intrigued by his tenacity. This leads to them forming an unlikely alliance against a common enemy. As they spend more time together, they start to understand each other's motives and personalities, and a unique bond forms between them.
One idea could be a time - travel twist. Maybe Bulma discovers a way to travel to a different timeline where Trunks is older and there's a complex relationship that develops between them, full of emotional turmoil and discovery. It could explore themes of love across different versions of themselves.
One idea could be Yamcha getting a new power-up. Maybe he discovers a hidden technique during his training in the wastelands. He could then use this new power to face off against an old enemy, like the Saibamen. This would show his growth as a character.
One idea could be that Bulma, while doing some research in a far - off planet, accidentally stumbles upon Broly. At first, Broly is hostile as he's used to being feared. But Bulma, being the smart and fearless woman she is, tries to communicate with him using her tech gadgets. She shows him things from Earth, like pictures of her family and friends. This makes Broly curious about Earth and he decides to follow Bulma back to Earth, leading to a series of adventures as he tries to adjust to this new world and protect Bulma from other threats.
Maybe there's a plot where Beerus has a premonition about a threat to the universe that only Bulma's technology can help prevent. So, he has to team up with her. Along the way, they learn more about each other's worlds. Bulma gets to understand the power and responsibilities of a god like Beerus, and Beerus discovers the amazing potential of Earthling technology. This could lead to a deeper friendship or mutual respect between them.
One plot could be that Roshi enters a cooking competition, and Bulma decides to help him out using her scientific approach to cooking. They combine Roshi's traditional recipes with Bulma's high - tech cooking gadgets and create amazing new dishes. Along the way, they face off against other competitors who are jealous of their unique approach. Another idea is that a strange alien race kidnaps Roshi, believing he has a powerful energy within him. Bulma uses her intelligence and resources to track him down and rescue him. During the rescue mission, they learn more about the alien race's motives and end up befriending some of the aliens who were against the kidnapping in the first place.
One idea could be that Bulma discovers a new technology that allows her to fuse with different characters' minds, not just their bodies in a traditional sense. She could fuse with Goku to understand his pure love for fighting and gain some of his combat instincts.
He could break her heart by cheating on her. Maybe he gets involved with another woman, and when Bulma finds out, she is devastated.
Well, it could be about Yamcha making Bulma cry perhaps because he said something really mean. Maybe he criticized her for being too obsessed with her inventions and not paying enough attention to their relationship.