Before I go into my answer, I should point out that where the theory of psychological projection originated from Sigmund Freud, his theories are considered by many as pseudoscientific. More can be read in my answer to this in meta
Definition of Projection
This is a psychological defence mechanism whereby beliefs, attitudes or other negative aspects from ourselves or the environment are attributed to others or other aspects of our environment (Reeves, 2013). Totem and Taboo by Sigmund Freud (Freud, 1913) contained his major thinking on the role of projection (Hurry, Novick, & Novick, 1976).
To list all possible forms of projection would be too broad for this site as it would fill a fairly thick book to do so with ample description. Below I will outline some examples which are on the WikiPedia pag linked in the question and alongside those examples will be references to books which you are free to read to gain more.
Examples of Projection
- Victim blaming
The victim of someone else's actions or bad luck may be offered criticism, the theory being that the victim may be at fault for having attracted the other person's hostility (Bingham & Tamarkin, 1985).
- Projection of marital guilt
Thoughts of infidelity to a partner may be unconsciously projected in self-defence on to the partner in question, so that the guilt attached to the thoughts can be repudiated or turned to blame instead, in a process linked to denial.
A bully may project his/her own feelings of vulnerability onto the target(s) of the bullying activity. Despite the fact that a bully's typically denigrating activities are aimed at the bully's targets, the true source of such negativity is ultimately almost always found in the bully's own sense of personal insecurity and/or vulnerability. Such aggressive projections of displaced negative emotions can occur anywhere from the micro-level of interpersonal relationships, all the way up through to the macro-level of international politics, or even international armed conflict (Jung & von Franz, 1964).
- Projection of general guilt
Projection of a severe conscience is another form of defense, one which may be linked to the making of false accusations, personal or political (Jung & von Franz, 1964).
- Projection of hope
Also, in a more positive light, a patient may sometimes project his or her feelings of hope onto the therapist (Casement, 1990).
Bingham, J. & Tamarkin, N. (1985). The Pursuit of Health: Your Mind, Your Body, Your Relationships & Your Environment. New York: Walker Press
Casement, P. (1990). Further Learning from the Patient: The Analytic Space and Process. Hove, UK: Routledge.
Hurry, A., Novick, J. & Novick, K. K. (1976). Freud's concept of projection. Journal of Child Psychotherapy, 4(2), 75-88. DOI: 10.1080/00754177608254963
Freud, S. (1913). Totem and Taboo: Resemblances Between the Psychic Lives of Savages and Neurotics Translated by A. A. Brill, 1919 London: George Routledge & Sons Limited
Jung, C. G. & von Franz, M-L. (1964) Man and his symbols. Garden City, N.Y. : Doubleday
Reeves, A. (2013). An Introduction to Counselling and Psychotherapy: From Theory to Practice. London: SAGE Publications Ltd.