I carry a tool bag with metric and standard wrenches, vice grip pliers, Gorilla tape, zip ties, a scan tool, multimeter, and a small electrical kit of wire, connectors, crimper, fuses, and a relay.
Sometimes I carry a ratchet and sockets.
The biggest thing is carrying tools you know you might need. If I'm in my '96 Ranger, I'm going to have the right sockets to pull my spindle and change an axle shaft.
In my 2021 I make sure I have the right size wrenches to tighten the bolt and nut on my Skyjacker upper control arm if it should come loose.
A tool kit like
@sgtsandman showed is a great idea because it doesn't take up a lot of space and everything is organized so you're not digging through a tool bag trying to find the tool you need that's probably on the bottom.