It would appear that the reliable rumormongers are talking about what the release schedule for 2015 will look like for 40K. Below is a summary of what is rumored to be coming out. These rumors are based on comments made by Hastings75 and Harry from Warseer.
-In No Particular Order of Release-
- Adeptus Mechanicus Codex & models (full release)
- Genestealer Cult Codex & models (Harelquin sized release)
- Deathwatch Codex & models (Harelquin sized release)
- Horus Heresy Standalone box game, on sale for a few months, then models become part of 30k range Mark 4 + Cataphract armors featured. (Harry believes the rumor of Mark 9 power armour is actually the new 30K range*)
- Assassins Standalone box game, on sale for a few months, then models become part of the 40k range.
- Greater Daemons all complete (2 in 2015, 2 in 2016, BT already confirmed, LoC believed to be 2nd release*)
- Dark Angels later in the year
- Tzeentch later in the year
*Comments added by John