Xbox controller dongle, SIP cordless phone base, BeagleBone Black, and a Mikrotik Routerboard (with 3 x R52Hn cards). We later swapped the drill battery for a LiPo pack and added a USB hub to make the Xbox dongle happier.
Our first attempt at power for the base station repeater was using 18V drill batteries. Worked great until we killed one due to drawing the voltage down too low – I guess there isn’t a protection circuit built into them.