I just bought myself a very smart tool called a spiral or ratchet screwdriver / drill, sometimes known as a "Yankee" drill. Spiral grooves in the shank convert pushing motion into turning motion, so that you can drill a hole or drive a screw simply by pushing the handle towards the target. The one I bought came with several types of driver bits as well as a drill bit.
It's entirely mechanical, so it doesn't require a power plug or rechargeable batteries, and is always ready to use. Yet it provides the convenience of a power tool. As is typical of so many other wonderfully clever inventions, it's out of favor and hard to find nowadays because everyone wants electric drills.
I remember that my Dad had one when I was a kid; I think it had been his own father's. I was reminded of this clever tool at Susan and Joel's worm-bin building bee, where a very helpful and knowledgeable carpenter named Guy Astley was using one. Several women formed a crew to assemble the sides and bottom of the bins -- they fell in love with the Yankee. They called themselves the Drill Team.
This is the kind of tool that I think it's smart to stock up on now. It would be great to have if electricity becomes hard to come by for an extended period of time.
Now I need something to build!
(BTW the model I bought was made by an outfit called Eazy Power. I had to return two of them for defects, but the third seems fine. There are other more-expensive brands that may be better.)