Maybe something like this. This is the size of a credit card, assumed 2 mm thick steel. There are four tools, A - D. Maybe they come on an adhesive backing that you peel off when you need to separate and use the tools. This is an emergency tool, gets used once, you don’t worry about how to fit it back neatly in the wallet.
Tool A is 4mm, 5mm, small flathead, small Phillips, file blade, saw blade.
Tool B is 6mm, 7mm, large flathead, large Phillips, serrated blade, and a leverage slot.
Tool C is 8mm, 9mm, chisel, and leverage notch.
Tool D is 10mm, 12mm, straight blade, and leverage slot.
Tool C can be inserted in Tool D’s slot to extend the handle on Tool D, which might be needed for those larger nuts. Tool C can be inserted through Tool B’s slot to form a T handle allowing you to press the driver blades into the screws and apply more torque. Tool C doesn’t have any blades on the sides, so it can be used this way.
Thoughts? Other/different tools? Any way to fit in a can opener? I decided a bottle opener is dumb, in an emergency you can always open a bottle. But if you’re in the desert with a can of pineapple juice, a can opener will be lifesaving.
This can’t be a commercial product, because you have to use your head or you’ll cut your fingers off while wrenching. Product liability lawyers will sue you out of business. But something like this could possibly be laser cut from good steel as a group make/buy for a small number of people who all sign waivers. I’d be inclined to let people grind and sharpen the edges themselves. Idea being if you can’t do that, then you may not be handy enough for this tool to do you any good. Also to reduce liability and cost.