During a 'who am i' phase during my adolescence, I tried quite a number of this sort of personality tests. There was only one that I found particularly valuable, because it discussed oddball traits in the resulting analysis. In particular, things like (some low percent) of this personality type have the ability to manipulate what they see. Examples include (some name) who could play entire 3D visualizations on top of the world around him. These 'oddball trait' descriptions were present when I participated in that beta test, but have vanished after they commercialized their product. For that reason I'm not going to say which company it was, as their one big differentiator is gone.
But it does raise a big question: I was particularly fascinated by such conclusions because nowhere in the questions was anything related to 'oddball trait' experiences: there were no questions asking if I had extra good spatial analysis abilities. This was somehow inferred. And that suggests that perhaps there's a link between the development of particular personality groups and uncanny abilities, which no one is willing to publish in test result analysis and which no one is willing to discuss for fear of being called a crackpot. Not that the abilities are necessarily bad, but in the case of our particular example it would be nice to know that 'extraordinary spatial analysis skills' is potentially linked to personality and experience, not something attained purely by training.
So that raises my big question: why are this sort of information being suppressed? Why are test results often taken as, you belong to this group, and so you should be doing this sort of work? This sounds to me very similar to communist-style work force distribution: you fit norm A, so go and do job B. Are such 'fit the pattern' psychology tests unintentionally turned into a method of normalizing and categorizing people into stereotypes, to push them into certain directions? Is there some sort of censorship going on here making particular rare behaviours and abilities inaccessible to general public knowledge?