There's a fanfiction where Tien and Yamcha are transported to an alternate dimension. In this dimension, they have to fight against versions of themselves that are evil. It's a really cool concept as it explores different sides of their characters and how they deal with seeing their own dark counterparts.
One possible fanfiction could be about Tien and Yamcha teaming up for a special training session. They might start off with some friendly sparring, showing off their unique martial arts moves. Tien could use his multi - form technique, while Yamcha demonstrates his Wolf Fang Fist. As they train, they start sharing stories about their past battles and how they've grown as warriors. Eventually, they come up with a new combined attack that could be used against future threats.
You can start by looking on popular fanfiction websites like FanFiction.net or Archive of Our Own. There are often many 'Dragon Ball' - related fanfictions there, and you can use the search function to specifically look for ones that feature Tien and Yamcha.
They could be part of a detective story within the Dragon Ball Z universe. Tien and Yamcha are hired to solve a series of mysterious disappearances. They start by interviewing different characters, like Bulma for any technological insights or Goku for any leads from his adventures. As they dig deeper, they find that the disappearances are linked to an ancient evil that was thought to be sealed away long ago. Using their martial arts skills and wits, they try to track down the source of the problem and put a stop to it.
For Yamcha, you can focus on his growth from being a bit of a comical character to a more serious and respected fighter in the context of his relationship with Frieza. Maybe he learns from Frieza's cold and calculating nature how to better strategize in battles. For Frieza, his development could be about him learning to care for someone other than himself. He could start to see Yamcha as an equal, which is a huge shift from his usual superiority complex.
One possible plot could be that Yamcha, known for his tenacity, somehow ends up in a situation where he has to team up with Frieza. Maybe they are both forced to face a common enemy that is even more powerful than Frieza at his peak. This could lead to an interesting dynamic as Yamcha tries to get Frieza to work as a team, while Frieza is his usual self - conniving and power - hungry. Their interactions would be full of tension and mistrust at first, but over time, they might develop an odd sort of respect for each other.
One common theme could be the exploration of their complex relationship. Given their history as rivals in the original series, fanfics might focus on how they overcome that to develop a more intimate connection. Another theme could be the power dynamics between them, as Vegeta is often seen as a more powerful character compared to Yamcha.
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 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.