The Raspberry Pi Zero has a terminal marked RUN
with two pins. This terminal could be used to reset the Raspberry Pi Zero. This is especially if the Raspberry Pi Zero is installed some place inaccessible. The Raspberry Pi Zero can be reset by connecting a momentary push button across the two pins. Because a momentary contact is sufficient to reset the board, this terminal can be useful where the Raspberry Pi Zero is installed at a very distant location, and it could reset using an Internet connection (provided that there is another device that controls the RUN terminal pins).
The location of the Run Pins on the Raspberry Pi Zero
Note
We also found this excellent tutorial to set up a reset switch for the Raspberry Pi - https://blog.adafruit.com/2014/10/10/making-a-reset-switch-for-your-raspberry-pi-model-b-run-pads-piday-raspberrypi-raspberry_pi/.