Knowing yourself can predict whether or not you will be content with your career of choice even before you start work. There are several free sites out there, but only a few are legitimate and fully free. Some of them on this list will require an email confirmation. Be assured that you will not receive any spam mail from the sites provided in the Personality Profile list. A few sites will promote you to purchase a full profile. A partial one is sufficient to get a good picture for the soft skills you can promote on your resume or in your cover letter.
Many of these quizzes have psychology background; however, a psychology degree is not necessary for interpreting the results nor is professional help required. You are identifying terminology necessary to promote yourself in your portfolio, digital brand, social media, and resume/cover letter.