Hi! Thanks for the compliments; we're glad that you're finding Storylark useful!
And yes, Storylark is open to comics containing LGBTQ themes. We are as okay with this as we are with straight romances!
That said, we're currently not sure about "LGBTQ" as a standalone genre, in the same way that "Romance," "Fantasy," and "Sci-Fi" are, as it's a theme or particular kind of content that may or may not appear in a variety of genres.
To deal with noting the themes of a story, we have the tagging system. (Users are free to create and use their own sets of tags, if desired.) These tags make comics more easily searchable, and make life easier for users who may or may not want to look at certain material.
That said, if there is a sufficiently large number of creators who consider "LGBTQ" a genre in and of itself, with its own conventions and story characteristics, then we can consider adding this in as a genre.
("Supernatural" can work as a genre, too, but right now we haven't separated it out from "Fantasy" or "Thriller / Horror" just yet. At the moment, it might be more correct to set a Fantasy or Horror as a genre, then pick Supernatural as a tag.)