Most likely if you are lining up to get a Moto Z Droid or Moto Z Force Droid then you are going to get a few Mods to go alongside with that. I might otherwise it would defeat the purpose of the phone right? In any case Verizon and Motorola see this and are looking to give you a 40% discount on each one you select after. These range from a battery pack, projector, speaker or just an additional case.
To get a better idea of how Moto Mods work check the video below as well as HERE