As of right now, we have books lined up in some form or another for the next few months. This month (which releases on Feburary 1st) will be a collection of classes including the Gunslinger. Next month (March) will be the Weird West update, which mixes swords, sorcery, and six-shooters in equal measure, and the month after that (April), we have something only called Dragonbook lined up.
(note: this is a tenative release schedule, subject to change, and at the whims of none other than the Finger himself)
We're running a poll for the book that comes after that. There's some great options right now!
Go hop on our Patreon and and vote!