A changing selection of open content

L.O.C. Image Sets
The US Library of Congress, (LOC), recently launched a new interface to make it much easier to find free to reuse open content. The featured image sets are, of course, just a small fraction of the LOC's free content, but they offer a great starting point for exploring the collections link 

Europeana works with thousands of European archives, libraries and museums to share cultural heritage for enjoyment, education and research. European makes it easier for people to use cultural heritage in education and for research, creation and recreation. Their contributes to an open, knowledgeable and creative society. Link

Victorian Illustrated Shakespeare
Michael Goodman's Victorian Illustrated Shakespeare Archive, is an online open access resource, (CC BY), with a database over 3000 high quality illustrations taken from published Victorian editions of Shakespeare’s works. 

Each image is presented as an original scan, together with edited B&W images. Detailed information including, size, media and provenance is provided for every illustration. 
Metadata in the form of an  intuitive word cloud is great for exploring the resource. Drop down menus that link to plays and characters also provide slick navigation around the database. It's fascinating to note how different illustrators interpreted the people, places, and artefacts in the works. A great resource for anyone studying Shakespeare, including schools. Link
David Rumsey Historical Map Collection
A spectacular collection of over 89,000 historical maps, charts and diagrams, available in high resolution. The collection includes pictorial, schematic and narrative maps. There are also tool allowing one to link, with and include geo-data. 

The collection is available using various search interfaces, of which the best is the Luna viewer search Link

The 78rpm Project
This Project by George Blood, hosted on  on the Internet Archive has digitised over 25,000 historic 78 RPM and Cylinder recordings. These include classics and also lesser known works covering many genres, including; jazz, country, classical in many languages.
Each recording includes a description and background information together with reviews and comments. And of the authentic sound of scratches! Link 
Note! Although the collection is offered for personal use and research some of the items may still involve copyright and use is the responsibility of the user.
Comic Book Plus
A historically significant archive of Public Domain Comics, which also includes some esoteric newspapers and magazines. A superb source of material for researchers, casual observers and digital artists and re-mixers. Link

Biodiversity Heritage Library
The Biodiversity Heritage Library is a consortium of natural history and botanical libraries that cooperate to digitize and make accessible the legacy literature of biodiversity from their collections and to make it literature available for open access and responsible use. As well as the main site you can easily access on their Flickr collection