I'm not sure about all of them, but if you search for his name along with 'visual novels' on specialized anime or game platforms, you should be able to find some. His work in voice acting for visual novels often gives a distinct flavor to the characters he voices.
Some of his works in visual novels might not be as widely known globally but are highly regarded within the niche community. His contribution to the genre is not only through his voice but also in terms of promoting the visual novel medium. His popularity might attract fans of his other works to explore the visual novel world.
There is also 'Steins; Gate'. Mamoru Miyano's contribution to the visual novel through his voice acting cannot be ignored. His ability to convey the complex emotions and thoughts of the characters makes the overall experience of the visual novel much more engaging.
Mamoru Miyano is also very good at using his voice to create a sense of character development. As the story in the visual novel progresses, his voice changes in a way that reflects the growth or decline of the character. This is especially important in visual novels where the story often unfolds over a long period and the characters go through significant changes. His voice acting helps to make these changes more believable and engaging for the audience.
Well, 'kissed by the baddest bidder' often involves some intense and passionate storylines. In a fanfiction about Mamoru, it could explore his character in new and exciting ways. Maybe it shows a different side of his personality that we don't see in the original work. It might also focus on his relationship with the main character, delving into the emotions and chemistry between them.
Love is a very common theme. Since Usagi and Mamoru have a strong romantic connection in the original story, fanfictions often expand on their love, like how they overcome obstacles to be together.