Listed here are some databases you can use to find online primary texts. The texts you find will either be in HTML or PDF format, and options for printing and/or saving materials will very greatly by database.
Below the name of the database is a short description of the time period covered in the databse, the number of and type of items available, as well as suggested ways to find relevant information for your class.
The databases listed below will help you find out information about primary texts but won't give you the actual primary text. Once you find the name of something, consider looking for the complete online version of the item in HathiTrust, or consider looking for the print item in the Special Collections Research Center (6th floor of Hatcher).