Which pins are unusable in an MKR 1000 and MKR Motor Carrier combo?

Not really sure where to ask the question in the header. I remember reading some where that when use with the MKR Motor Carrier some of the MKR 1000 pin are unusable because motor carrier uses the ports for some thing else. I want to use one of the output ports to power a motor (all the other ports are full). Which ports can I use and can I connect to the GND?

NoIdeas22:
I want to use one of the output ports to power a motor (all the other ports are full).

What do you mean by "output port"? Are you really wanting to use it to power the motor, or only controlling it?

NoIdeas22:
can I connect to the GND?

Yes. Of course, the MKR Motor Carrier uses ground, but this doesn't prevent you from connecting other things to the GND pin.