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.
No. Abuse is never an appropriate topic, especially when it involves beloved characters from a popular series like Dragon Ball. It goes against the positive values that the series usually promotes.
A popular Yamcha fanfiction is 'Yamcha's New Beginnings'. In this one, Yamcha decides to start anew after feeling left behind by his friends. He goes on a solo adventure, meets new allies and enemies, and in the process, he redefines himself and his place in the Dragon Ball universe. It gives a fresh perspective on his character.
Interesting strong Yamcha fanfics often give him new relationships or character dynamics. Like he could form an unexpected alliance with a former enemy, and through that, his character develops in new and exciting ways. Also, if the fanfic delves deeper into his backstory and uses that to fuel his new - found strength, it can be really engaging.
Some Yamcha fanfictions might center around his training. He could be training with different masters in these stories, or even discovering new techniques on his own to become stronger in the Dragon Ball universe.
Fanfictions can vary widely in their themes and content. In the case of 'yamcha abuses bulma fanfiction', it's a rather disturbing concept considering the characters. In the original Dragon Ball series, Yamcha and Bulma have a past relationship that was not like this at all. So this fanfiction might be an attempt by some writer to explore extreme and negative situations, but it's not something that would be considered positive or in - keeping with the general feel of the Dragon Ball franchise.
To my knowledge, there aren't any sad story porn comics with Yamcha. Such content would be quite unusual and may even be against the law in many places.
There were a few novels that fit this description, such as Legend of the Earth Emperor, Mountain God in the City, Incense Becomes God, I Actually Became a Mountain God, and so on. You can choose one according to the plot introduction of these novels and your own taste. I wish you a happy reading!