Hard to say. While the Star Wars franchise has a wide range of stories to tell, this one seems a bit more niche. It depends on how much interest there is in exploring the political side of the Star Wars universe on such a large scale.
One possible fem clone OC could be a highly skilled sniper. In fanfiction, she might have unique markings on her armor that distinguish her from the male clones. She could befriend some of the Jedi, like Ahsoka Tano, and together they face various challenges during the Clone Wars.
In 'Naruto Senate Star Wars' fanfiction, a common theme is the exploration of different forms of governance. The Star Wars Senate has its own political structure, and when Naruto characters are introduced, it allows for a comparison and contrast. Another theme is the role of the Force and chakra. Some fanfictions might explore how the concept of chakra from Naruto could interact with the Force in the Star Wars universe, especially in relation to the Senate's power and influence. Additionally, the theme of identity can be seen. Naruto characters may struggle to maintain their own identities while also becoming part of the Star Wars Senate - related events and politics.
There might be a fanfiction where a Senate Guard forms an unlikely alliance with a rebel. The Senate Guard realizes the corruption in the Senate and decides to use his knowledge of the inner workings to help the rebel cause. This could lead to many exciting adventures and moral dilemmas as the Guard has to betray his original post.
One interesting clone fanfiction could be about a clone's journey of self - discovery outside of his military duties. For example, a clone might start to question the purpose of the war and his place in the galaxy.
One unique plotline could be a time - travel story. A character goes back in time to the start of the Clone Wars and tries to prevent certain events from happening. Another could be a story where the clones develop their own culture and start to question their purpose. And there's also the plotline where a Jedi falls in love with a Separatist, creating a conflict of loyalty.
I'm not sure as it doesn't exist yet. But if it were to be made, we might expect political intrigue within the Star Wars universe. Maybe it would show how the Senate functions during different galactic events, like the rise of the Empire or the Clone Wars.
Obviously, the Senate Guards themselves are essential. Their unique armor and loyalty to the Senate make them interesting. Also, senators like Padmé Amidala can be included. Her political influence can create great storylines when interacting with the Senate Guards.
You can start by looking on fanfiction websites such as Archive of Our Own (AO3). It has a large collection of fan - created works, including many for 'Star Wars: The Clone Wars' and specifically about the clones.
Themes in this type of fanfiction can be quite diverse. The idea of self - discovery is a big one. Clone troopers start to question their purpose and place in the universe. Another common theme is the relationship with the non - clone characters, be it the Jedi, the civilians, or the Separatist forces. How they interact and how their relationships develop is often explored. And of course, the theme of following orders versus doing what is morally right, as clone troopers are trained to follow orders but sometimes face moral dilemmas during the war.