Board Thread:Questions and Answers/@comment-85.128.131.1-20150814023529/@comment-25035274-20150907202726

He sells buttons. He also does sell physical books, but they're only available at Japanese conventions or through Japanese retailers/web sites. He doesn't have any distribution outside of Japan at present.

Other MG material that might be worth looking at include (in the game range) Monster Girl Quest or the Violated Hero series, though those can both be a bit darker than MGE in over-all theme.

On the Manga/Anime side of things, there's Everyday Life With Monstergirls. Not sure there's really a whole lot else dedicated specifically to MGE-style monster girls. The MG genre as seen in MGE is a relatively recent-ish thing.