Many professions that tend to be highly individualistic and require complex mastery have historically been represented by a Guild. While Guilds these days are sometimes a specialized form of union, the distinctions are often significant. A couple examples that come to mind are the American Bar Association, the American Medical Association, the Screen Actors Guild, and the Writers Guild of America.
Well, at least in the case of SAG and the WGA, those are essentially just white-collar unions. Neither of those groups would describe themselves as pro-organizing, but opposed to unions.
