One idea could be a time - travel fanfic where Bulma accidentally sends Goku back in time to a period before they met. Goku has to figure out how to get back while also dealing with the differences in that time period. Another could be a story where Bulma creates a new device that gives Goku a new power - up, and they have to test it out against a new, powerful enemy. A third idea is a fanfic set in an alternate universe where Goku and Bulma are the rulers of Earth and have to deal with diplomatic issues with other planets.
A plot idea could be that Bulma discovers a hidden Saiyan ability in Goku that he was unaware of. They then embark on a journey to explore and master this new ability. Maybe there's a prophecy that only Goku and Bulma together can fulfill, which involves saving the entire universe from a mysterious dark force. Or perhaps Bulma's scientific experiments go wrong and she and Goku get stuck in a dimension where they have to rely on each other more than ever to find their way back home.
A plot could involve Bulma creating a new device that Goku needs to use in order to defeat an extremely powerful enemy. Goku has to learn how to operate this device with Bulma's guidance, and they face many obstacles along the way. This would show their cooperation and how their different skillsets complement each other. It could also lead to some comical moments as Goku tries to understand the complex technology. Another interesting plot could be that they are both transported to an alternate dimension where the rules of the Dragon Ball world are slightly different. They have to figure out how to adapt and find a way back home while also uncovering the secrets of this new dimension.
A possible plot in the 'dragon ball goku and bulma lemon fanfiction' could be that Bulma is working on a project that requires a special ingredient or power source that only Goku can help her find. As they search together, they encounter various challenges like dangerous terrains and powerful creatures. Along the way, their friendship deepens and they learn more about each other's strengths and weaknesses. This could lead to them developing new powers or techniques that they bring back to their friends in their normal world.
One idea could be a story where Bulma creates a new device that accidentally sends Goku and her to a parallel universe. There, they have to work together to find a way back home while facing new and strange enemies. Another could be a time - travel plot where they go back in time to before Goku met Chi - Chi and Bulma realizes she has feelings for him. The third idea is a story where Goku and Bulma get trapped on a deserted planet and must rely on each other's skills to survive and escape.
One interesting plot could be a time - travel scenario where Goku and Bulma end up in an alternate timeline together. They might have to face new threats that are different from the ones in the main story. Another could be a story where they go on an adventure to a new planet and discover a powerful energy source.
A possible plot is that the other Z - fighters are in shock when they find out. Vegeta, in particular, could have a complex reaction as he has his own relationship with Bulma. He might be jealous or protective in his own way. Also, the fanfiction could focus on how Goku and Bulma's child might inherit both Saiyan strength and Bulma's intelligence, and what that could mean for the future of the Dragon Ball universe.
A plot could involve Caulifla being from a parallel universe where she is the only survivor of her race. Goku meets her during a multiverse tournament and decides to help her. As they train and fight side by side, they develop a deep bond that goes beyond friendship and they explore their new relationship while facing various challenges from other universes.
One interesting plot idea could be that Frieza somehow manages to gain new powers on a distant planet and returns to challenge Goku again. But this time, instead of just brute strength, he uses cunning strategies. Another could be a scenario where Goku and Frieza are forced to team up against an even greater threat from another universe. This would be a great chance to explore their complex relationship.
A plot idea could be that Goku Jr. discovers a mysterious artifact that has a connection to the Dragon Balls. As he tries to figure out its purpose, he gets caught up in a race against an evil group who also wants the artifact for their own malicious plans. This could lead to him making new allies and having to use his wits as well as his strength. He might also have to face some personal challenges, like doubting his own worthiness to be a hero, similar to how Goku in the original series sometimes had self - doubts.
Perhaps a fanfiction where Vegeta and Goku get transported to an alternate universe. In this universe, their roles are reversed, and they have to adapt to the new situation while still trying to find a way back home. They would face challenges that are unique to this new world and learn from each other in different ways.
One interesting plot idea could be Goku training Caulifla in a new form of Ultra Instinct. This would allow for a deep exploration of their mentor - mentee relationship. Caulifla is already a strong fighter, but with Goku's guidance, she could reach new heights. Another plot could involve them teaming up against a powerful new enemy that neither could defeat alone. They'd have to combine their unique fighting styles and powers to win.