Update: the sale is now 12 packs for $14.99, extended until Oct 12. New in the bundle: Fantasy RPG Bosses — 6 big 192x192 animated bosses (Minotaur, Lich King, Red Dragon, Demon Lord, Slime King, Dark Knight) with an enraged second phase, 3,048 frames.
Bundle: Complete Pixel Art Collection. Requests for the next pack are welcome!