You know you can use some more zombies.
Everyone can always use more zombies.

Source
From the announcement:
All Zombie Hordes on Special
Here is your chance to fill your game table with hordes of zombies
Get Zombie Horde I (100 figures) or Zombie Horde II: First Responders (100 figures) each for a special price.
Or choose the Zombie Horde I&II Combo (200 figures) that gives you both sets for one special price never before offered.
Find them in the Specials Section of the Victory Store