Looks like another combination that works just as well as Yuri + Classical music is Yuri + Sci-Fi. Here is an ongoing yuri sci-fi action story written by Yuri Council member Dr Animaniac. This is The Valkyrie Princess.
In the year 2530, the world has been reformed after the deadly attack by the Kree 500 years before. These humanoid aliens invaded, craving the high levels of Carbon and other elements in the height of the earth’s global warming crisis. However, these elements could also be found in human blood, leading the Kree to attack humans. The brave warriors known as the Valkyries rose up and fought, saving humanity from total ruin. The world became a green utopia and natural preservation is strictly enforced to avoid another crisis and the potential for another invasion. Although fewer, the Kree still roam certain regions and pose a threat. Therefore the Valkyries continue to defend their respective citadel regions from them as Valkyrie Princesses. Amelia, a charming, boyish, warrior, is the next in line to become Armenia’s new Valkyrie, but then she meets Ellisia. This peculiar, but kind and beautiful girl changes everything and upon meeting, their tragically beautiful love story begins.
The interested can read the book and look forward to future chapters by creating a Movellas account HERE for free. The site accepts Twitter, Facebook or Google+ accounts in case visitors have no interest in creating an account from scratch.