For completely unmarked wrenches I'll go along with:
A - tools supplied with heavy machinery (farm equipment, industrial machinery, printing presses, etc) for basic adjustment/maintenance
B - tools in basic kit bags for early autos, motorcycles, bicycles (particularly the ultra cheapy flat stamped wrenches), also for basic adjustment/maintenance
or C - bulk boxes of cheap wrenches on hardware and Five ' n Dime store counters.