The "Images" tab has a few suggestions for where you can start. But here are some more ideas.
Archive Grid - includes over four million records describing archival materials, bringing together information about historical documents, personal papers, family histories, and more. With over 1,000 different archival institutions represented, ArchiveGrid helps researchers looking for primary source materials held in archives, libraries, museums and historical societies.
Europeana - Explore the digital resources of Europe's museums, libraries, archives and audio-visual collections. It promotes discovery and networking opportunities in a multilingual space where users can engage, share in and be inspired by the rich diversity of Europe's cultural and scientific heritage.
The Internet Archive Movies - This library contains digital movies uploaded by Archive users which range from classic full-length films, to daily alternative news broadcasts, to cartoons and concerts. Many of these videos are available for free download.
The Internet Archives Still Images - This library contains digital images uploaded by Archive users which range from maps to astronomical imagery to photographs of artwork. Many of these images are available for free download.
Library Databases (links are 'proxied' so you'll be prompted to log in when you click on them)
American History in Video - Provides the largest and richest collection of video available online for the study of American history, with 2,000 hours and more than 5,000 titles on completion. The collection allows students and researchers to analyze historical events, and the presentation of historical events over time, through commercial and governmental newsreels, archival footage, public affairs footage, and important documentaries.
Black Studies in Video - Features award-winning documentaries, newsreels, interviews and archival footage surveying the evolution of black culture in the United States. In partnership with California Newsreel, the database provides unique access to their African American Classics collection, and includes films covering history, politics, art and culture, family structure, social and economic pressures, and gender relations.
Kanopy - Provides a streaming platform and a broad catalog of over 26,000 streaming videos to choose from, representing more than 800 leading producers.
Oxford Art Online - Enables access and cross-search functionality to Grove Art Online, the Benezit Dictionary of Artists, the Encyclopedia of Aesthetics, the Oxford Companion to Western Art, and the Concise Oxford Dictionary of Art Terms. Includes image partnerships with ARTstor, the British Museum, the Museum of Modern Art, the Metropolitan Museum of Art, Art Images for College Teaching, Art Resource, Artists Rights Society and numerous international art galleries and artists.
There are lots of resources out there the include letters, diaries, travelogs, news stories
The Internet Archive Texts - over 8,000,000 fully accessible public domain eBooks. This includes a special modern collection of over 500,000 eBooks for users with print disabilities, and a very interesting curated, modern collection for the world at large.