Indeed, Christian fiction, for one, is appealing to increasing audiences with more and more "crossovers" with mainstream appeal - you can find religious epic fantasy, romance, science fiction (particularly apocalyptic), mysteries, novels dealing with contemporary issues, self-published novels, historical fiction set in the era of Downton Abbey - that try not to dilute the values of Christian literature but "are expressing their faith and the interpretation of it through their writing in fresh new ways". Sometimes this means publishers will provide books with an overtly religious message "alongside books that are clean, fun, and inspiring but not overtly religious". You are also more likely to see authors marketed to millenials, especially, on Facebook and Twitter and books about Friends-style groups.
Here's a list of some new and novel Christian fiction from the library catalog, from a variety of genres. Why not try one out and see what you think?
