I put together a small tool kit that I always have in my range bag. It is stored in an old Outers metal cleaning kit box so it isn't too big to carry in the range bag. In there are cleaning rods for handguns, a .22 rifle and shotguns, screwdrivers commonly used on S&W and Colt handguns, some common hollow ground flat screwdriver bits for rifles, a few common Allen wrenches, a few torx bits for sight mounting screws, Hoppe's solvent, oil, cleaning patches, Rig gun grease, a Range Rod, bronze and nylon tooth brushes, a few Bore Snakes of different calibers, a very small gun smithing hammer, pipe cleaners, a few pairs of tweezers, a set of assorted bronze and nylon bore brushes and brass patch loops, some nylon picks and a few other small tools I am probably forgetting about. Oh - I also have a few new single edge razor blades and some masking tape wound around a #2 pencil. That is about it and I have used this small but viable kit many times for helping out fellow shooters (and myself from time to time) who have a simple issue I can repair at the range. Anything more complicated gets done back in my workshop.
BTW, this sounds like a lot of stuff, but it really does fit snugly into the old cleaning kit box and has been added to several times over the years on a "need basis". Now I think it's just about right.