Jim and 62bass have excellent lists. Both will keep you out of trouble on any gig. Highly recommended.
This list is ridiculously exhaustive. However, the tools fit into a relatively small (16") lockable tool box. The tooling is the same as the shop. If you are not a repair tech, it is still a good idea to keep all of your luthiery tools in one container. Another good idea is that each tool has a place in the tool box. There is nothing worse than rummaging around looking for something to complete a five minuter repair six minutes before you are scheduled to take the stage.
Stuff other than repair tools like cables and picks go in to a separate bag or box. Both containers live behind the amp.
Don't skimp on the stuff for others. An extra E string or drum key goes a long way to making a good impression when you are freelancing and can cement your position in a new band.
Previously posted:
Gig Survival kit Guitar/ Patch Cables all 95% shielding
One extra for each in my signal chain
One each 1’, 2’ 3’, and 10’
Speaker Cables One extra for each in the chain
One each 3’, 6’, and 15’
StringsBass strings (1 set)
Electronics Multi meter
Cable tester
AC ground tester
Assorted AC to DC adapters
Wire
2-9 volt batteries
Fuses
Power cable
25-extension (12-2)
6 slot power strip (extra)
FlashlightsMini-Mag light (6”)
Head lamp (LED)
Tools Precision screwdrivers (short kit in plastic box)
#1 and #2 philips
#1 flat blade screw driver
Allen wrenches, metric and SAE
Side cutters (dikes)
Slip joint pliers with soft jaw covers
Electrician’s pliers
Soldering iron (25 watt)
Rosin core solder
Steel probe
Utility knife
String winder (bass and guitar)
Small hammer
Miscellaneous Duct tape
First aid kit
Super glue (liquid thin, for split nails)
Super glue solvent (self evident)
Butane lighter
Matches
Couple of dollars in quarters
Business cards (band and personal)
Small note book, pen, and pencil
Real Book/Fake book for genre
For others Guitar picks
Drum key
Guitar string sets (1 nickel electric .009, 1 acoustic bronze light gauge)
Replace above as necessary