The common themes in croma male fanfic could be quite diverse. It might include themes of power and its corrupting influence if Croma is in a position of power in his original story. Or it could be about redemption if he has made some mistakes. It could also involve themes of family, either his own family or the family - like bonds he forms with his comrades. Additionally, exploration of new places or concepts within the fictional world of Croma could also be a theme.
There could be a croma fanfic that focuses on Croma's relationships. For example, Croma forms an unlikely friendship with a character from a different species. They overcome their differences and together face various challenges in their world.
I'm not sure specifically about 'croma male fanfic'. But you can try searching on fanfic platforms like Archive of Our Own. There might be some stories related to characters named Croma that are written by fans.
I'm not sure of specific croma fanfic writers off - hand. But you can start by looking at fanfic platforms. Often, the ones with the most views and positive reviews are written by talented writers.
One theme that often shows up is the struggle for power. In 'alloy and male fanfic', male characters might fight over control of an alloy mine or the formula for a special alloy. Also, friendship is a theme. Male friends might work together in a workshop, experimenting with different alloys to create something amazing.
One common theme is the underdog story. Often, the male character starts out as an unknown or underestimated figure in the RWBY world and has to prove himself. For example, in many fanfics, he might be a new student at Beacon Academy with a lot to learn.
Since I'm not aware of many such fanfics, it's hard to say. But it could potentially explore themes of friendship across species, cooperation in a shared adventure, or perhaps cultural exchange between the two characters.
Power and magic can be a theme too. If it's in a fantasy setting, they might be dealing with different powers or magical elements. For example, the male OC could have a special power that Aqua helps him to control, or they might be on a quest to find a powerful magical artifact together.
Since'male birth mlp fanfic' is not a common type, it's hard to define common themes precisely. But perhaps some might explore the idea of family in a different context within the MLP universe, like how a male character deals with the new role of being a parent.
One common theme is isolation. The male character often feels alone and cut off from the world. Another theme is internal struggle, like fighting against one's own negative thoughts. And there's also the theme of hope, sometimes in the form of a new relationship or a self - discovery that gives the character a reason to keep going.
Some fanfics focus on the theme of support. In a 'male x mirio' relationship, they support each other through difficult times, whether it's dealing with personal problems or challenges in their hero - related tasks. It shows a really positive and heartwarming side of the relationship. And of course, there are also fanfics that play with the theme of the power dynamics between the two characters, which can lead to some unique and exciting plotlines.