"Psychometrics includes the measurement of knowledge, abilities, attitudes, personality traits, and educational measurement. The field is primarily concerned with the construction and validation of measurement instruments such as questionnaires, tests, and personality assessments." (1)
Like an icebreaker at a party, these tools provide a formalized way of getting over the initial hump when you try to jump-start self-discovery. Just like the many "lets extend our relationship even further" games like the 'Ungame', there are psychometric tools that can help you go further into self-discovery than the average person would go without help.
You have to ensure that you take everything with a grain of salt, that you use the tools as a jumping off point, and don't get sidetracked or influenced by them, but with those caveats, psychometric tools are a great jumping-off point for getting to know yourself.
The tools listed on this page are in different stages of evolution. None of them would be considered fully vetted psychometric tools, but my aim is to increase the interaction with psychometric tools and reduce the barrier to interaction. Part of that is to promote the amateur creation of psychometric tools. If you have created a rudimentary tool to assess something important to you, and used it for a while, I believe you will get much more out of a professionally produced tool with years of academic research behind it – and I believe that you will be more able to critically assess that tool by comparing it with your amateur effort.
First question: who has control of databases of the various tests? Put them in a spreadsheet with the following 'columns':