• OER Commons: A leading OER search engine and community. Here you can find tens of thousands of accessible teaching materials and tools to publish your own teaching materials online. You can also find groups with subject-specific materials.
• Open Education Consortium: A multidisciplinary database with different types of teaching materials.
• Merlot.org: One of the largest multidisciplinary databases with many different types of accessible teaching materials.
• Academic Earth: A large number of video clips from, among others, MIT, Stanford, Berkeley, Harvard, Princeton, and Yale.
• Khan Academy: Hundreds of short teaching videos on a vast array of subjects. It contains a particularly large science and maths collection.
• University of The Netherlands: A database of free lectures from top Dutch scientists.
• Wikiwijs: A Dutch platform for free digital public teaching materials. This sub-page focusses on higher education.
• Open University: MOOC’s and free courses in an array of subjects.
• Edge Sage Group: SAGE edge offers open access tools and sources for both students as well as lecturers. Examples include exams, syllabi, PowerPoint presentations, articles, and videos.
• Oxford University Press Resource Centre: Free supplementary materials for Oxford University Press books such as exams, videos, and PowerPoint presentations.

Open Courseware is a collection of open teaching materials that are freely available in the form of a course. A course can combine different types of teaching materials such as video lectures, assignments, or discussions.

A list of universities that offer open courseware:

• MIT Open Courseware: ​A website with all of the courses that MIT developed: open and freely available.
• University of Michigan: ​The University of Michigan offers a large amount of open teaching materials, open data, and open publications.
• University of Leicester: ​The University of Leicester’s Open teaching materials.
• Delft Open Courseware: ​A platform with a great amount of MOOC’s and courses.
• Leiden Open Courseware: ​A platform with about 30 MOOC’s and courses on subjects such as law, language, mindfulness, counterterrorism, and music in society.
• University of Nottingham: Free mutidisciplinary courses from the University of Nottingham.
• Yale Free Courses: A selection of introductory courses taught by lecturers and scientists at Yale.
• Open Learning Initiative: Carnegie Mellon University: Free and paid courses for both students and lecturers.

A Massive Online Open Course (MOOC) is an online course that is open to an unlimited number of participants. A MOOC is open and freely accessible (unless you want a verified certificate). Be sure to always check the conditions under which you are allowed to use the materials.

The following portals offer freely accessible MOOC’s:

• University of Amsterdam: ​Online Coursera-courses on subjects such as methods and statistics, communication sciences, and media-ethics.
• Coursera: ​A platform with free courses on a great number of subjects. The UvA is affiliated with Coursera.
• EdX: ​An MOOC platform with university level courses, of which a few are freely available. EdX was founded by MIT and Harvard University but affiliates also include TU Delft and the University of Wageningen.
• Iversity: ​Originally a German platform for higher education. Iversity collaborates with both universities as well as individual lecturers/professors.
• OpenupEd: ​An open, non-profit European platform that offers free MOOC’s for higher education.
• FutureLearn: ​Originally a British platform with MOOC’s covering an array of subjects. One must pay for access to the exam, getting a certificate, and continued access to the course upon completion.
• OERu: platform that offers free university level courses. It offers both ‘full courses’ and ‘micro courses’. The micro courses are part of a full course.

Open textbooks are textbooks with an open copyright license which means it is permitted for them to be freely available online. The conditions under which these textbooks may be used, including editing and distributing the information, have been set forth in a Creative Common’s license. Open textbooks are currently very popular in the US. While this might not yet be the case in the Netherlands, this does seem to be changing. Open textbook providers usually do require payment for a printed copy of the open textbook.

A few platforms that offer open textbooks:

• Saylor.org/books: Open textbooks on business, management, accounting, social sciences, science and maths, communication, and personal development. The books are available under a CC BY-NC-SA 3.0-license.
• BC Campus OpenED: Open textbooks on business, trade, art, education, tourism, health, law, engineering, and social sciences.
• Book Boon: A platform with both paid and free textbooks that can be downloaded as a pdf-file. The subjects offered include business, economy, marketing, management, accounting, career- and study advice, languages, IT, engineering, maths and statistics, and physics.
• Open Textbooks Library: An open textbooks platform that offers freely available books on most subjects
• Open Stax College: Open textbooks on subjects such as business, the humanities, the physical sciences, maths, and the social sciences.
• Connexions: A book platform from OpenStax CNX Library with books on Art, Business, Humanities, Mathematics and Statistics, Science and Technology and Social Sciences.
• Edtechbooks: Platform with open textbooks that can be easily adapted.
• SUNY OER Ready-to-Adopt Courses: Platform with open textbooks that can be easily adapted.

Publishers’ websites often include a section offering teaching materials that complement their books. Here you can find multiple choice questions and their answers.

• Oxford University Press Recourse Centre
• Book Rags Lesson Plans
• Edge Sage Group

For older photos you can go to the image banks of archive institutions. The Startpagina Beeldbanken (Dutch only) gives a handy overview.

• On the  Europeana website you will find images of objects in European museums, libraries and archives.
• Press photos can be found on the websites of ANP (Dutch only), Reuters, Spaarnestad and LIFE.
• Pixabay offers a wide range of free to use images, as well as Free Images where it is possible to search through a topic guide.
• You will find a wide range of partly free and free-to-use images on Flickr. Filter on “all creative commons”.

If you want to know more about an image, use Google Images. Click on the camera icon and upload the photo. You can filter images for usage rights via Google images via Settings> Advanced search> Usage rights.

Edusources is a repository service for universities of applied sciences that serves to make publications, theses, and teaching materials accessible and easy to share. The knowledge products are connected to the ‘HBO Kennisbank’ and Netherlands Research Portal. The teaching materials are visible in Wikiwijs. This repository service complies with the current standards for saving work in a sustainable manner and making sure its freely accessible.