Project Gutenberg
See below for relevant collections from this free, online library eBook resource:
The Internet Modern History Sourcebook
Hosted by Fordham University, this site offers a collection of public domain and copy-permitted historical texts presented cleanly (without advertising or excessive layout) for educational use. Primary sources are available here mainly for use in high-school and university/college courses.
The African American History Curatorial Collective (AAHCC)
A division of the Smithsonian’s National Museum of American History, this collection is meant to promote the research and interpretation of African American history. Members of the AAHCC are curators, based in divisions across the museum, who specialize in African American history.
The Library of Congress
The Library of Congress is the largest library in the world, with millions of books, films and video, audio recordings, photographs, newspapers, maps and manuscripts in its collections. The LoC has several Digital Collections related to Africans American History & Literature. You are also able to search within their entire digital collection using your own search terms.