Myers-Briggs, The Spirit Controlled Temperament, and now most recently the Predictive Index. I may even have been exposed to the test for the Five Factor Model at a past job, but since I wasn't told what the test was for or my results I can't be sure. But all these different bucketing mechanisms are cut from the same cloth - a fun little party game taken way too far to the point where management gets all giddy about it and hiring decisions are made off of it and there's a multi-million dollar a year consulting industry built up around pigeon holing people into these buckets and pretending like this one simple test with 86 subjective questions is real science. And people buy it in droves.
I don't doubt the rationality of some aspects of these categorizations. Certainly it's obvious that there are some people who like organization, and others chaos. Some people get energized by being around people, and some by being alone. Some people like to be the boss of everything, and others would prefer to make things work behind the scenes. Everyone is different in their motivations and expectations, and those things have an effect on people's interactions with each other. But that information is only so useful, and not everything is so black-and-white. Humans are complicated, and these "tests" over-simplify who we really are by elevating the results to be predictors of what makes us us - what we'll enjoy, what will make us happy, how we'll perform a particular job. It limits people's potential for change and growth, instills a monoculture of personality in workgroups, and frankly makes some people become really neurotic.
In a noble attempt to better understand each other, what these tests actually wind up doing instead is lumping people into categories that may or may not be accurate in any or all circumstances. In trying to help us understand each other, I think it actually makes us understand each other less. You start seeing people as High A, or Low B, or middle C, or High D. Blue, Red, Green, or Yellow. ISFP or ENTJ. Left-brained or right-brained. It limits our ability to see who others really are, and their potential to change and grow beyond our limited view of which bucket they fit into today.
Sometimes this sort of stereotyping has value, but often it's taken too far. Some people like to label themselves. Most people like to label others. Marketers and pollsters love to convince you that people are merely categories and are totally predictable. Sometimes true. But not always. These tests are merely a weak attempt to bring pseudo-science into the high-art of human relationships. Oh, and to line the pockets of many a consultant.