black/white drawn illustration of a man in a tricorne hat dressed in clothes from the 18th century, hand outstretched, as a torrent of books, scrolls and papers seemingly whirl past him in a sea of paper and parchment.

Here is a collection of links to various resources around the net that I have found handy. Note that they may have changed their license terms or other bits since I added them to the list so make sure to read through any agreements etc before using them.


Images

Comic Book Plus – Everything from newspaper serials to full comic books that are in the public domain.

Old Book Illustrations – public domain images scanned from old books. Offered up royalty free. The image at the top of this page (An ocean of books) is from OBI.

Unsplash – Free stock photographs released under their Unsplash License.


Charts, diagrams and similar

Data Wrapper – create high quality maps, tables and charts. Has a free option.

Diagrams.net – from timelines to org charts, system layouts or illustrative pictures, Diagrams.net (formerly Draw.io) is an invaluable resource.


Misc

The Public Domain Review – online journal showcasing various public domain works.