If it seems like DC has been slow in expanding their Earth One graphic novel line in the last few years, things definitely look to be speeding up now. Teen Titans: Earth One has been solicited for release in November, and new entries in the Batman: Earth One and Superman: Earth One series will be released in 2015.
We don’t know a great deal about either Batman: Earth One Vol. 2 or Superman: earth One Vol. 3 yet, but DC recently debuted the covers to both books via The Nerdist.