There are a few useful commands to get information about devices that can be used to help solve problems. They are all done via SSH.
List the available devices:
cat /proc/bus/input/devices
Get information about USB devices:
lsusb -v
Get information from udev about devices that were mapped in an event:
for i in /dev/input/event*; do echo $i;udevadm info -q all -n $i;done
Get a list of all buttons/axes/keys found (even if it is a keyboard):
for i in /dev/input/event*; do echo $i;(evtest $i) & ( evtestpid=$! && sleep 0.1 && kill -15 $evtestpid );done
Whenever you run one of these commands, it is best not to paste the entire output to the forum or Discord. Instead, use something like http://pastebin.com/, paste what is displayed after you run the command, and then give the link to the people you are communicating with.