Ayahi Takagaki - Next Destination:
A Symphogear social game (presumably iOS) is in development. Oddly enough it appears they are using the 1st season designs. Not many details are known but the above image states Hibiki, Tsubasa and Chris's actors will be recording for the game.
Tsubasa has been confirmed as playable in Super Heroine Chronicle.
If you buy the 3rd volume of the Symphogear manga from gamers you get this special illustration print.
The August 2013 issue of Megami Magazine includes this Symphogear G poster.