History is the study of the past, which means history can about almost anything. That, in turns, means that historical primary sources can be just about anything.
In practice, however, primary sources are actually the materials--text, illustrations, maps, or baskets--which allow scholars to get as close to their specific research question as possible. That means, if you are studying the history of human rights in South Korea in the 1950s, you need to find material on human rights from South Korean in the 1950s. Material from the United States in the 1930s won't cut it.
For more, visit BC Libraries' Asian History Research Guide for more country specific collections.