In addition to what Astro said, the leaker for the Underworlds warbands was correct about Pirate Ogre and Frankenstein Zombies if I remember correctly, and said one of the next bands would be Clan Eshin.
Whilst Underworlds isn't tied to AoS' releases too much, The Crimson Court did coincide with the Soulblight Gravelord BT and the Thunderstrike/Kruelboyz warbands were only a couple of months after Dominion.