A couple factions look like they will be getting new Battletomes in the near future. Chaos getting a Battletome: Everchosen, and the Dwarves getting the Steamhead Duardin and the Fyreslayers.
Here is the latest coming for the Age of Sigmar.
via Lady Atia on War of Sigmar
There should be a campaign, and atleast two new battletomes, one this year, one early next year ;)
*hint hint, a new, old, but new faction*
"Old Dwarfs" (essentially the last big plastic wave) = Steamhead Duardin
Slayers + some elements of the Chaos Dwarfs (no hats, but the fire theme) = Fyreslayers