I use a rolling pelican, and while there always is at least an adapter kit on a gig, I do bring adapters I always use such as playbak adapters, iem adapters (1/4 trs to mini female), and things that arent normally around in abundance such as nl4 turnarounds and isoblox.
The rest of the kit usually contains:
Mouthwash/alcohol wipes/paper towels for personal and microphone clenlines
Wireless router
8ch audio interface and ref mics
Rf scanner
Board tape
Half case of AA and 9v
Handfull of various Zipties
~10ft of bailing wire
Allen keyset
Multibit screwdriver
Jewlers screwdriver set
Multimeter
Voltage detector
Various snips/sidecutters/wire strippers/pliers
C wrench
Ratchet straps
Small slings/beeners
Test cds
Various collected misc adapters (bnc barrels, rca turnarounds, etc)
SPL meter
Laser distance measure
Compas
Bubble level
AC Cube taps
Various cat 5, db9, usb adapters
Handfull of ear plugs for clients/punters
Medical scrub brushes and 3" painters brush for mics, consoles
I put a fedex declaration package on the lid for small odds and ends/PD cash
Plus probably more that squeaks in thats there that I've forgotten until I need it.
BRad