The activities of psychologists are very diverse. The types of psychologists can be grouped in various ways. The attached image is one of the grouping in terms of academic, medical and applied psychology.
According to the British Psychological Society (BPS), psychologists normally specialise in a particular area such as education, health or sport, and Psychology is a huge scientific discipline and the Society confers Chartered status in the following areas:
The details of their work can be found in http://careers.bps.org.uk/area/newcareer/i-want-be-psychologist-what-type