Here are some of the great classical theories of Psychology. This is just an outline of important school of thoughts that I have learned.

Analytical Psychology
   This is oriented in the ideas of the Swiss Psychiatrist Carl Jung.
   Its aim is the personal experience of the deep forces and motivations underlying human behavior.

Associationism
   The theory which states that consciousness is the result of a combination, in accordance with the law of Association of simple and ultimate elements derived from sense of experience.

Behaviorism
   This is also called as learning perspective.
   It is a philosophy of Psychology that is based on the proposition that all things which organisms do - can and should be regarded as behaviors.

Cognitivism
   Is the theoretical approach in understanding the mind, which argues that mental function can be understood by quantitative, positivist and scientific methods and that such functions can be described as information processing models.


Functionalism
  Theoretical level between the physical implementation and behavioral output.
  Has philosophical underpinning of much empirical research in Psychology and cognition.

Humanistic Psychology or Humanism
   Is explicitly concerned with the human dimension of Psychology and humans.
   It emphasizes the idea of freewill on human beings.


Purposivism or Hormic Psychology
   It is primarily concerned with "striving" or having a purpose.
   It has something to do with the role of hormones.


Psychoanalysis
   A family of psychological theories based on the works of Sigmund Freud.
   It seeks to discover the connection among the unconscious components of patient's mental processes.

Structuralism
  This refers to various theories which shares the assumption that structural relationship between concepts may vary between different cultures or languages and that these relationships can be usefully exposed or explored.

Aside from the above School of Thoughts, here are some known theories of Psychology.
Gestalt Psychology
Individual Psychology
Existential Psychology
Social Psychology
Ego Psychology