The four temperaments idea had been present in our noosphere for a very long time. In the ancient Greece, there was the notion of four temperaments present in their medicine, where each temperament presented one of the human liquids and their balance and imbalance caused the person's personality: melancholic, choleric, sanguine and pragmatic.
Even in the scientific cycles the temperament idea showed a couple of time. Pavlov came up with the idea of the two dimensions, where different combinations bright forth four different personalities. He apparently found this out by observing dogs, but I am not sure, as the original citation is written in Russian and I don't read Russian.
Eysenck also originally proposed 4 personalities, divided based on the introversion and neuroticism. He later added another dimension, so he doubled the possible types.
Keirsey also created the temperament theory, but his was more aligned with the MBTI types. He divided types into SJ, SP, NT and NF temperaments.
The SJ are called traditionalists. Some other people call them logistic as well, and I think that the both description fit. I remembered once reading the comparisons that they are the people that make sure that all the necessary resources are where they need to be. They are actually people that make sure that everything is continuing as normal. Be it by making sure that bureaucracy and organizations are working as normal, or by making sure our social organism we call a society is going on as normal. SJ means that they are using Si function with either Te or Fe combination. So they are combining the subjective feeling about things with changing their outside world. For example, they would believe that family needs to be the most important thing, so they would change their system and society to adhere to this notion. Or you can subtract some other policies here, like life is secret, people have the right to free speech, climate change is important/useless and so no. They like the clear lines, which is why, considering that they have low openness (S) and high conscientiousness (J), they tend to vote conservative.
The SP are called the experinecers, or I also saw them called artists. These are the people that you want next to yourself in a pinch. They are really good at the reacting in the stressful situation, some more in a logical and detached way and some with the value based system. But they at least won't freeze when there is something to be done, but there is not clear order what to do next (something my sister claims that I do, and I am worse than her in this regard). They are the doers and they don't really appreciate the people's daydreaming. They are using the Se function with the combination of either Ti or Fi function. So they see and perceive their outside world, which do they apply the logical or value oriented rules to it. Their Se function allow them to be the people that enjoy the moment, the feeling of driving, the taste of a good food and so one. They can be just a bit impatient at the time, when things are going slowly.
The NT are called rationalist or conceptualizers. There are people are constantly try to go deeper and wider in their quest for knowledge. They are either coming up with the new ideas or cutting through all the unnecessary information to get to the mist important gist of the problem. Unlike the previous two temperaments, this one, along with the next one, is a lot less practical in their everyday life. A lot of people say, that this temperament is also striving for always higher competence (which is true), and because of that they have a great self-confidence (not necessary true). They are using either the Ni-Te or Ne-Ti combination, which means that they both look for ideas and apply logical models to it, but the difference is that the Ni-Te people use their internal ideas and intuition (Ni) that they try to then change the outer world in accordance to it (Te). In the other hand, the Ne-Ti combination looks for all the new ideas and possibilities in the outside world (Ne), and than applies the model to them in order to evaluate them (Ti). That is why they are usually a lot direct and truth-oriented.
The last one are NF, which are called idealists. These are people that are so concerned with the meaning and feelings, that this sometimes seems like their most predominant feature. Be it with the overall meaning of the world or just the potential of the people that they meet, there people can be a source of new insights. They are striving for a living and sometimes the world that works in accordance to their values or values of the people around them. Just like the previous one, here they are also two difference, they can either use the Ne-Fi combination or the Ni-Fe combination. So either they are using the eternal truth that they intuit is right and try to correct the outside world in this way, in the Ni-Fe combination. Or they are using the outside ideas to try and live the life in accordance to their values and make sure their values, and maybe also values of other people, are respected. I have the feeling that the people that want to safe the world, and really mean it, are most likely of this temperament.
So this are just short descriptions of my current limited and stereotypical view of the temperaments.