how to sell android icon packs on Play store

i feel like i'm in the twilight zone...
i can barely search the play store for any type of android app, without half the results being an icon pack of some sort, free and/or paid. but a simple www.google search with the broadest terms i can think of ("sell android icon pack") yields 0 (ZERO) relevant how-tos, tutorials, books, or discussions worth a damn. this blows my mind, given play store saturation.
can you please help? links to info / instructions for beginners, suggest different search terms, etc. i'd like to develop something like this: https://play.google.com/store/apps/details?id=com.jndapp.line.x.iconpack&hl=en_US.
thanks