[EricH]

Use of a screwdriver. (And the difference between flathead, phillips, and "Who put the specialty screws on here?")
Use of measuring devices of various types--scales, calipers, micrometers, tape measures--and marking devices--markers, scribes, and the like.
Use of hex keys.
Use of a ratchet and socket set, including a wide range of attachments.
Proper use of a hammer.
Proper use of a hacksaw/chopsaw.
FILE USAGE.

Basically, any "standard shop tool" (drills, wrenches, drivers, measuring, cutting, and "percussive" tools) will be both incredibly useful and highly transferrable. Tapping could be included, but tends to be more of a niche use.

"Medium" tools (drill press, bandsaw of both types) would be next--you'd need to have the tool, though.

"Advanced" tools--like a lathe and mill--build on the others.

CNC equipment... There's professional training for that in a few years if someone goes that route.