For the purposes of helping with the setup and maintenance of my guitars (primarily the Epiphone
SG-400) I picked up this selection of tools.
I have a series of small screw drivers to be used when tweaking the pickup heights as well as for adjusting the bridge saddles for intonation purposes, feeler gauges (from an automotive store) for checking string heights at various frets when resetting the action, and a couple of rulers showing 1/16" and 1/32" divisions for checking string heights at the pickups.