Gray-collar

But if you look at the employment trends in the country, you find that the white-collar (and gray-collar) activities have become increasingly important...

Source: wiktionary

1964, National Ice Association: Forty-Seventh Annual Convention, Democratic Party Convention, OK State Fed of Labor Your present plan is rated, not for the so-called blue collar people, it’s rated for white-collar and that thin gray line, the gray-collar worker. In many small businesses you don’t know who is blue-collar and who is white-collar, the boss often doing all kinds of work around the firm.

Source: wiktionary

1971, Richard Patrick Coleman, Social Status in the City, Jossey-Bass, page 68, At the lower-middle level, the typical Negro male was a gray-collar worker in one of the civil services, worked for the railroads as a Pullman porter or dining car waiter, or owned a small business.

Source: wiktionary

1989, United States Senate Committee on Governmental Affairs, U.S. Efforts to Commercialize Superconductivity: Hearing Before the Committee on Governmental Affairs, United States Government Printing Office, page 152, Vocational training reaches greater fractions of the labor force in nations like West Germany; large Japanese companies invest more heavily in job-related training for blue- and gray-collar employees than do American firms.

Source: wiktionary