For example
Common primary source keywords include:
You can also try keywords for kinds of primary sources:
Remember to evaluate the sites you find -- even a quick check to see if a site is produced by an archives, museum, governmental agency, or educational institution can help you determine whether this is a legitimate, trustworthy source for information. The best sites for primary sources will provide you with the information you need to cite your sources.
To see if a librarian has already identified digital primary sources related to your topic, do an Internet search for a term or phrase related to your research plus the phrase "research guide" or LibGuide.
Amherst College Digital Collections
Collections from other institutions
Collections organized by era
Collections organized around slavery and abolition
Collections organized around social identities & social histories
Collections organized by geographic region
Collections organized around political histories and political activism
These databases have collections of newspapers published generally pre-1990, often digitized from print or microfilm. They are searchable, but be aware that the results won't be as accurate as born-digital newspapers.
Use these to find freely-available collections of primary sources.