Since 'Star vs the Forces of Evil' has themes of magic, different dimensions, and growing up, in futa fanfiction these could be intertwined with the futa concept. For example, a character with futa characteristics might have a different relationship with magic or how they interact with other dimensions. Also, relationships between characters, like Star and Marco, could be explored in new ways that are influenced by the futa elements in the fanfiction.
Love and sacrifice is another big theme. Since it's a fanfiction about a relationship (Tomstar), there are often stories where either Tom or Star has to make sacrifices for their love. It could be sacrificing their own desires or even their powers in some cases. Also, the exploration of their relationship in different universes or timelines is quite common. Writers like to play with the idea of what if they met under different circumstances, which adds an interesting twist to the stories.
One common theme could be the struggle between good and evil, with the 'naked star' representing a form of good or a unique entity against the forces of evil. Another might be the transformation or evolution of the 'naked star' as it battles the evil forces.
One common theme is the adaptation of the characters' powers to the gaming world. For example, Star's magic wand might work differently in a game setting.
A common theme is cuteness. Since it's about babies, it often focuses on the adorable aspects of the characters as infants. Another theme could be discovery. Babies are constantly learning, so in these fanfictions, baby Star or other characters might be discovering their magic for the first time in a really innocent way.
One common theme is friendship. Since Marco has many friends in the show, fanfictions often explore the depths of his friendships, like how he supports his friends and how they support him in return.
One common theme is friendship. Even though Tomco is often seen as a romantic pairing, a lot of fanfictions build on their friendship first. They show how Tom and Marco support each other through different challenges.
Finding good 'Star vs the Forces of Evil' futa fanfiction can be a bit of a challenge. First, futa fanfiction is a rather niche genre within the already diverse world of fanfiction. Second, the legality and ethical aspects of some fanfiction can be a bit murky. While some platforms may host such works, they may also have rules against certain types of content. You could try reaching out to dedicated 'Star vs the Forces of Evil' fan communities to see if anyone can point you in the right direction, but don't get your hopes too high as it may not be a common type of fanfiction for this particular show.
Love and friendship are also big themes. Their relationship is often portrayed as a complex mix of both. In some fanfictions, they start as friends and slowly realize there are deeper feelings. There's also the theme of forgiveness. Given their past conflicts, they have to forgive each other for things that have happened. This can be really well - explored in fanfiction, like when Star forgives Tom for his outbursts in the past, and it helps them move forward in their relationship.
One common theme is identity. Since Marco is now a female, exploring how this new identity affects her relationships and her role in the story is often seen. For example, how does she interact with Star differently now? Another theme is power. Some fanfictions give Fem Marco new powers, and the exploration of how she uses and controls these powers is a big part of the story.
One common theme is the clash of different power systems. Star has her magic from the 'Star vs the Forces of Evil' universe, and Goku Black has his Saiyan powers from Dragon Ball. Another theme could be the exploration of good and evil. Goku Black is a villain, so stories might focus on how Star and her friends deal with his malevolence. Also, the idea of interdimensional travel can be a theme, as Goku Black is from a different universe in Dragon Ball and would have to cross into Star's world.