One possibility is that their time travel could be accidental. Maybe Android 18 was working on some new device and it malfunctioned, sucking in Kid Goku as well. Once they are in the past or future, they could end up changing the course of history. Kid Goku's pure heart might influence Android 18 to become a better 'person' in a sense, and they could form an unlikely alliance to fix whatever problems their time travel has caused.
Well, they could end up in different historical events. Maybe they land during the Saiyan - Tuffle war. Kid Goku might be confused but Android 18 could use her knowledge of history (if she has any in this fanfic) to guide them. They could also meet different versions of characters, like a younger Vegeta or Gohan.
In this time travel fanfic, Android 18 and Kid Goku could have some really interesting interactions. Since Kid Goku is more naive and Android 18 is more... well, robotic and sassy. They might get into all sorts of trouble. For example, Kid Goku might see some strange future technology with Android 18 and try to use it as a toy, not realizing its potential power.
At first, they might be at odds. Kid Goku is used to his own world and Android 18 is a product of a much different time. But as they face challenges together during their time travels, they could start to respect each other. For instance, Kid Goku might admire Android 18's strength and Android 18 could be intrigued by Goku's simple - minded yet brave nature.
Well, the plot could be that Goku and Android 18 are sent back in time by a powerful enemy's time - warping device. They end up in a time when the Saiyan race was still thriving on Planet Vegeta. Goku, being a Saiyan himself, is conflicted about interfering with the past. Android 18, on the other hand, is more interested in finding a way back. But as they stay there, they start to realize that there are things they can do to make the future better, like preventing certain evil Saiyans from doing terrible things that would later have far - reaching consequences for the universe.
One possible scenario in this fanfiction could be that Android 18 and Goku are forced to time travel due to a new threat that endangers the entire universe. They might travel to a time when the Saiyans first arrived on Earth. Goku, with his knowledge of the future, could try to change some events to prevent future disasters. Android 18, with her strength and unique abilities, would be a great ally in this adventure. They might face challenges like dealing with the primitive technology of that time and also having to hide their true identities to avoid disrupting the timeline too much.
Well, in a fanfic, Kid Goku and Android 18 could have an interesting dynamic. Kid Goku is pure - hearted and always eager for a good fight. Android 18, on the other hand, is tough and has her own sense of justice. Their interaction might start with a misunderstanding. Maybe Goku mistakes 18 for a bad guy at first because she's an android. But then, as they get to know each other, they could end up teaming up against a common enemy. Goku would be impressed by 18's strength, and 18 might be a bit amused by Goku's naivete.
There could also be a moment of self - discovery for both of them. Goku might see his past self in Kid Goku and realize how far he has come, while Kid Goku could get a glimpse of his future potential through meeting his adult self. They could share stories about their friends and enemies, like how Goku could talk about Vegeta and Frieza to Kid Goku, and Kid Goku could tell Goku about his early battles with the Red Ribbon Army.
They could go on a quest to find a powerful dragon ball that has been lost. Goku's sense of adventure and 18's combat skills would be a great combination. Along the way, they would face various enemies. Goku would use his super - fast speed and powerful attacks, while 18 would use her android abilities like energy absorption to deal with the threats.
One possibility could be a story where Android 21, with her unique powers and intelligence, teams up with Goku to face a new and powerful enemy. Maybe they start off as reluctant allies, with Goku being a bit wary of Android 21's past as an android. But as they fight together, they learn to trust each other and their combined strength becomes a force to be reckoned with.
A possible plot could be that Android 18 and Goku are thrown into an alternate dimension where they have to rely on each other to survive. In this dimension, they face challenges that test their friendship and fighting skills. Android 18 might learn some of Goku's signature moves and Goku could learn more about the technology within Android 18.
Well, they might become friends. Goku, being the kind - hearted boy he is, would probably be curious about Android 18. Maybe they'd start training together, with Goku showing Android 18 some of his martial arts moves. And Android 18 could show Goku some of her advanced technology - like knowledge, if she had any in her android form even as a kid. They could also get into all sorts of adventures, exploring the world around them and getting into harmless little troubles.
In a fanfiction where Kid Goku meets Future Goku, one possibility is that Future Goku would be amazed at seeing his younger self. He might share some of the dark experiences he has had in the future, like the battles against powerful enemies and the losses. Kid Goku, being young and full of energy, could be inspired by Future Goku's strength and determination. Maybe he would start training even harder, eager to reach the level of his future self.