AIM provides a list of open access textbooks that meet the AIM editorial board's evaluation criteria (linked at http://aimath.org/textbooks/evaluation-criteria/)

"The Chemical Education Digital Library Living Textbooks are online textbooks which cover a variety of topics including general and physical chemistry. Some of the Living Textbooks are editable or customizable to your course."

Full lesson plans and science project ideas on contemporary science topics. This site also includes a Live Access Server which provides real data sets for classroom use.

The National Institutes of Health is a clearinghouse of varied kinds of biotechnology data sets to download and use. Tools to analyze the data is also included.

The National Stem Consortium STEM Bridge Strategy grant project will include course materials available to every college in the U.S. by the end of September.

Free interactive simulations covering a diverse topics designed by the University of Colorado available in various languages.

A nonprofit research institute funded though donations and research contracts (its website notes that “RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.”). Publications include research monographs, reports, and more. Available as downloadable PDFs (and sometimes EPUBs).

UCI has made "a full undergraduate education's worth of classes available for immediate incorporation in part or in full by institutions of higher education or by individual professors."