My local library database has access to this website:

Data Axle Reference Solutions (Formerly ReferenceUSA).

Most likely your library will have the same website in its database. It is free to use and you search all sorts of companies with various criteria (i.e. Revenue, Company Size, SIC Code, NAICS Code, etc.)

Proprietary search is a confusing and difficult topic. I am going to start sharing what I learn on a weekly basis so that way other people can learn along with me as well.