Gohan will most likely encounter other Z - fighters like Krillin and Tien. They were all part of the group back then. Also, there's a good chance he'll meet Master Roshi. Roshi was a key figure in Goku's training, so his interaction with Gohan could be really interesting. He might also come across Bulma, who was always involved in the Dragon Ball story, either by accident or because he needs her help with some time - related technology or something.
He might be surprised at first. After all, having his tail back is a big change. He could start to explore the new sensations and abilities that come with it, like better balance perhaps.
In this fanfiction, Gohan might change important events in the past. For example, he could prevent certain villains from getting stronger or save characters who died previously.
Perhaps it was the result of a special training or a new form of energy absorption. Gohan might have been exposed to a new type of ki or energy that stimulated the regrowth of his tail. For example, if he was in a place with a high concentration of a certain type of energy that interacted with his Saiyan cells in a way that caused his tail to grow back.
The relationship could develop out of a need for companionship. Gohan, having lost many of his friends and family in battles, is in need of someone who can understand his pain. 18, being an android with her own complex past, also longs for someone to be close to. They meet and initially just offer each other a listening ear. As they talk more, they find that they can comfort each other in ways no one else can. This emotional connection then grows into a romantic relationship, and finally, they marry as they realize they don't want to be without each other.
It could be many characters. Maybe it was Videl. In the Dragon Ball series, Videl is a strong - willed girl, and she has a connection with Gohan. So in the fanfiction, it might be her that Gohan thought was cute.
Gohan may become more confident in relationships. In a harem situation, he has to deal with multiple people interested in him, which could boost his self - assurance.
One possibility is that it could be a genetic anomaly. Maybe something in his Saiyan genes that was dormant suddenly activated, causing the tail to grow back. In the Dragon Ball universe, Saiyan genetics are complex, and there could be some unexplored factors at play.
One possible fanfiction could be about Sentinel Prime and Optimus Prime having to work together to save Cybertron from a new, powerful enemy. They might start off with some differences in their approaches but gradually learn to combine their strengths.