Please remember that this is based off of rumors, a most of them very solid,
Rumors (italics are known or already released information)
Farsight Enclave: Digital: Already Released, Print: October
The Black Legion- Digital: August, Print: October or later
White Scars: September
Ravenguard: This year
Ultramarines: Q1 2014
Beil-Tan: Q1 2014
Tau Mercanaries: Q1 2014
Saim-Hann: Q2? or later
Those are the rumored codex supplements as we speak. As I get more information of course I will get to you.
The following are a series of my own personal speculations. Please note that there are no rumors yet pointing these directions. Journalistic speculation follows:
I expect that supplements for the following supplements to fit within the above timelines.
Orks, possibly speed freaks
Tyranids: Hive Fleet Behemoth (the hive fleet that fought the Battle of Macragge)
Chaos Marines: I expect another supplement. Not sure of its direction. (Night Lords Please)