We're on the road almost 8 months a year, very often we are far from any kind of service. Therefore our needs may be greater.
We carry a bottle jack, a 12 volt air compressor, a breaker bar for stubborn lug nuts, a set of short and long sockets, a drill, assorted screws and bolts, a hacksaw, hammer, assorted screw drivers, assorted tywraps, lockjaw pliers, a large wrench for the ball's nut. We carry an air pressure gauge, a plug kit for tires
(the most common tire failure is a nail or screw). We also carry pipe tape (blue) for water and gas (yellow) connections.
On the electrical
side we do carry assorted connectors, some wire, a small meter, wire strippers and crimpers.
I know it sounds like a lot but it doesn't take up much space. The biggest things, compressor, jack, breaker bar, tire repair, gauge,a small set of tools, battery
jump start ride in the tow vehicle so we always have them with us.
The one not mentioned is my Leatherman, I've had the same one for 14 years and use it every day for something.
I'm sure I forgot something but others will chime in....I also carry duct tape, painters tape and vhb tape.