Conversation starter: what kind of backplate modules would you like to see for the Moto Z?

Now, of course, this would not be the first time we see a modular phone hit the market — just 3 months ago, LG announced the G5 with its CAM Plus and Hi-Fi Plus modules, but those were a bit underwhelming. The fact that you have to power off the phone to exchange modules, the actual usefulness of the add-ons, and them still being hard to obtain to this day has users feel less than excited for the G5's alternate parts.
According to the rumors, the Moto Z modules will be separated in two categories – StyleMods and MotoMods. The former would just be alternate back covers that let you color your phone to your preference. The latter are modules that expand the phone's functionality. Leaksters say that one MotoMod would be a Hasselblad photography back cover, which will not only feature a dedicated shutter key, but an actual extra lens as well. A JBL audio module and a projector module have also been rumored.

But we are curious — if you were to have your way, what kind of module would you want to see for the new Moto Z phones? Or, if it already exists in our list of leaked modules, what kind of features would you want to see on it to make it worth your time and money?