A second wave of models is apparently due for sometime around June, and includes a Tzeenthch flyer. Not to mention that we are looking new Furies that can teleport short distances. Definitely check it out.
Please remember that these are rumors
via Stickmonkey on the Bols Lounge
This round of rumors is regarding the Second Wave, penciled in for June. Note however that Games Workshop has this thing for releasing Daemons in August - so that second wave might slide a little.
In any case, onto the waves themselves:
Keeper of Secrets/(Named GD of Slaanesh)
Lord of Change/Fateweaver
Furies/(Chaos ground daemons...I've heard this alternate kit unit has an "unstable" rules granting them an extra save, a 12" teleport, and a chance to lose models (determined randomly).
Hounds of Khorne
An all new Tzeentch Flyer... (NOT the Heldrake)
Chariot of Tzeentch/ Flame cannon alt kit)