Successfully complete the indicated task to get the corresponding Exterminator card:

Ace Hardlight: Get 4,000,000 Dread points.
Eviserator: Get over 100 Max Nanotech.
Shellshock: Get all weapons and Omega mods.
Reactor: Buy all the Mega weapon versions, including the Harbringer.
Vox's pet: Successfully complete all missions on the highest difficulty setting.
Vox: Get all skill points.