"Anything that has been created by a person who witnessed or experienced an event as a contemporary would be a primary source. Examples of primary sources would include letters, diaries, autobiographies, and contemporary documents such as newspaper articles, government documents, and oral histories." --Tim Watts
These databases cover a diversity of publications and time periods and are typically digitized copies of documents, so that you can see them in as close to their original form as possible.
These databases include primary sources like: