I used to carry a zillion tools - but over the years I have pared down to the following.
1) credit card/cell phone
2) jumper cables
3) electric stuff (multimeter, electric tape, cutters, etc)
4) eternabond/patch stuff, tarp/bungee cord.
4) multi purpose screwdriver, adjustable wrench, few sockets/driver
5) duct tape, liquid nails.
6) beer (in case I need to borrow tools from neighbor).
Last one is important - never forget that one of your neighbors likely carries a zillion tools and will not only loan you one but may even fix the problem for you.