The Chart Toppers Authoring group has a few more pony songs in the works for Rock Band 3. Included this time around are the following:
Eurobeat Brony ft. Odyssey - "Discord (EuroChaos Mix)"
Dasha and The Living Tombstone - "Good Girl"
Eurobeat Brony ft. Odyssey - "Luna (NIGHTMARE MODE)"
Jeff Burgess - Trixie
None of them have specific dates yet, and will be separate DLC purchases. Hopefully all you Rockband players out there see them soon though!
And head on down past the break for their announcement video!