Great idea. Most of us handle this by having on hand the "normal" stock of hand tools and then buying the oddball socket or wrench needed to do the job. "normal" might be defined as a standard collection of Sears 1/4 and 3/8 drive sockets, a collection of combination wrenches, etc. Then note any oddball tools needed in addition to those, like an 18 mm socket (not included in most sets) or wrench, or a hex driver, or whatever. That would make the database easier to compile, since it would be by exception only.