On this page, we present a few lists of OER repositories (websites where you can download OER) and search engines (websites where you can search through multiple repositories at once). These sources for OER differ from the other lists in that they have materials in multiple formats, such as books, courses, articles, and multimedia, and therefore cannot easily be fitted into other categories.

There are a number of points that may be relevant to you as you use this page to find relevant OER:

• There are two lists: one general, and a short one with more subject-specific materials. Due to the broad nature of these repositories, a more fine-tuned distinction is not possible. For the resources in the "other" list, we have listed the main fields associated with the resources found there.
• These lists are generally ordered based on usability, breadth, and perceived quality of the listed website, with likely more useful websites being listed first. However, this ordering is subjective, and therefore may not align with your experience of the listed websites.
• Related, these lists are not compiled by subject experts in the specific field, the ordering cannot be used as indication of the quality of the specific OER found by these repositories and search engines. We suggest using the evaluation criteria in our guide on searching for and evaluating OER to help you judge the quality of the OER found on or via these websites.
• It may be that some listed websites provide resources that are not open, but only free, or require further login to fully access the listed resource. As much as possible, we'll try to indicate the general license information for the resources on each website, but we strongly recommend closely examining the license for any resource that you may wish to start using.

If you have found an interesting website or resource on or via this list, and you want to know how you could start using it, the OER support services are here to help. You can reach us at: oer-library@rug.nl.

This list has websites that (search through other websites that) host a variety of different types of open educational resources (OER), with no field being the most prominent.

• Edusources - CC licenses - Repository for all types of OER from Dutch IT cooperation SURF. The University of Groningen posts their OER here first. Collection is steadily growing, has complete metadata per material, and easy license information
• City University of New York OpenED - CC licenses - CUNY's page on OER Commons. CUNY is a leader in OER field, and this provides a nice introduction to one of the biggest OER repository. Good metadata and license information
• OASIS - Varied - Polished search engine that searches through many other OER websites. Good filters for fine-tuning your results
• BC open collection by BCcampus - CC licenses - Fast website with many different types of OER, filters for easy searching, and good license information
• OER Commons - Varies - The staple OER repository. Beware that copyright-restricted, but free materials can also be posted here. Many fitlers and good license information
• Ontario Open Library - Open licenses (CC, GNU GPL) - Repository with different types of OER, a lot of H5P modules, and good metadata and license information
• GoOpenVA - CC licenses - Go Open VA's page on OER Commons. Has a smaller collection, whilst benefiting from the power of OER Commons
• MERLOT - Varied licenses - One of the biggest and well known repositories of OER. Be sure to check license information, as it also can contain copyrighted materials
• Open Research Library - CC licenses - OER repository with clear license information, good filters, and easy search options

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• City University of New York academic works - Varied licenses - Slightly clunky website in appearance, but with a good search function and proper filters to find materials. Also, most of these OER are tested through being used at CUNY
• Open Oregon Education Resources - CC licenses - Multimedia and interactive textbooks for full courses. Hosted on the popular Pressbooks platform
• OpenALG - Varied CC licenses - Open Education projects in the forms of books and ancillary materials. Scope is a little limited compared to bigger repositories
• Teaching Commons - Varied licenses - Search engine for all types of OER in many different fields. Website is a little clunky, but good way to browse popular OER

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• OAsis Commonweath of learning - CC BY-SA - Repository with different OER collections. Website design requires a little getting used to, as a lot of information is displayed at once
• Galileo - CC licenses - Repository and search engine for books and ancillary materials. Clear information for books, but the ancillary material section is a little harder to get through
• OpenUCT - CC licenses - Repository for the University of Cape Town. Some collections seem a little dated
• Bielefeld Academic Search Engine (BASE) - Open licenses (CC, GNU GPL) and Public Domain - Search engine with good filters, but also displays a results that seem less relevant such as info pages or biographies
• Library of Congress - Varies, also copyright protected materials - Repository of materials of the US Congress. Lots of information, but also has copyright protected materials in their collection
• COOL4ed - - Collection of resources by Californian educators. You can search per topic and class to find OER, although the collection is small. Good license information and reviews, as well as full reviews of actual educators using some OER
• ROAM Pennstate - CC BY-NC-SA - Courses and modules for a number of different courses. Website looks professional and has a lot of information, but no easy browse function, and the search also gives info pages and staff pages, which muddy results
• DataCite Metadata Search - Open licenses - Metadata search engine which can help you find al manner of texts, images, and datasets. Due to it searching for metadata, you still need to find the resource on original websites

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• Solvonauts - Varied licenses - Search engine on a simplistic website that lacks a good search function, but does have detailed metadata and license information
• Zenodo - Varied licenses - Well known repository for data and software, but also hosts texts and articles. A little technical in its look and feel, and can most resources are not directly educational in nature
• Illinois OER - Open licenses and Public Domain - A search engine/referatory for all types of OER. Website has an unsafe connection, and a slightly cluttered design, which makes searching difficult. Also contains more general information in searches which is less useful for educational purposes
• Open Michigan - CC licenses - Course packages with assignments, syllabi and slides for a range of fields. Has no search function, bur easy enough to browse through
• Internet Archive - Varied licenses - Repository and search engine. Famous website archiving much of the internet, including OER. Can be a little overwhelming as it scope goes beyond education
• OpenCulture - Varied licenses, also copyright protected ones - Blog/list style full of free materials, and some open as well. Can be an interesting perusal, but likely a little too general when looking for fundamental aspects of course design 

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• Wikiwijs - Cc BY(-SA) - Dutch repository for OER. Seems to be mostly redirected at HBO/MBO or high school however, so less useful for university courses
• Mason OER Metafinder - Varied licenses, generally open - A search engine that trawls through many of large repositories. Can be a little slow at times, and the amount of options returned means that you need a good search strategy
• WISC online - CC BY-NC - Animations and videos explain many concepts in many fields, as well as many exercises. Level may be a little too simple for university, and Flash player animations are no longer functional and therefore not interactive
• Siemens Media Portal - CC BY-SA - Database of texts, videos, and other resources for all types of fields. Permissive license and fast website, but generally aimed at high school education or earlier
• WorldCat Open Access - Open Access and open licenses- Large search engine with a lot of material that also go beyond the scope of education. Does not always directly link to resource, and license information is lacking

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• KlasCement - CC licenses - Belgian (Dutch) repository for all types of OER. Requires registration to download, lacks clear license information, and is mostly focused on non-university education
• Utah State Digital Commons - CC licenses - Different types of OER from Utah State. The website lacks a clear browsing feature, making navigation difficult, and a lot of the materials are quite dated
• OE Global OE Week 2022 Resources - CC licenses - Showcase of top OER from 2022. Nice collection, but no unified theme or audience, so more inspirational than directly practical

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• UBC Open Collections/cIRCle - Varied, also copyright protected ones - OER from different databases of the University of British Columbia. Results also give a lot of historical references and photos, so hard to find educational content
• Sun West Resource Bank - CC licenses, but also copyrighted materials - OER Commons page of Sun West. Most linked materials can already be found on other websites, and the amount of copyrighted materials is quite high

This list has websites that (search through other websites that) host a variety of different types of open educational resources (OER), mostly situated in one or several connected fields. This is indicated in the text next to the link.

• Smart History - CC BY-NC-SA - Art history repository full of courses, syllabi, and multimedia. Split up by time periods and geographic areas, which allows for easy browsing, and uses an open license

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• Skills Commons - CC BY - Practical and technical skills website. Has courses for self-training, and links to degrees. Metadata is really clear, and general license is very permissive. Interface is a little cluttered, so can be a bit difficult to navigate at first

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• Umbra Search - Varied licenses, also copyrighted - US/African-American history search engine. Lots of images, documents, and scanned texts, but with varying licenses, which can make reuse difficult
• Public Domain Review - Public Domain - Database of Public Domain resources, which are by extension often historical in nature. Contains many types of materials and generally has clear license and metadata, but clear educational purpose may be missing

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• Digital Public Library of America - CC licenses, but also has copyrighted materials - US anthropology and history search engine. Quite broad database for US history, and not directly aimed at education
• The Daily Idea - free, but often not open - Philosophy search engine with syllabi, reading lists and resources. Interesting collections, but many copyrighted resources
• Digital Library of the Caribbean - Often free, but not open - All sorts of materials on and from the Caribbean, but license information is sometimes missing, and subject is very niche

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• Candid Issuelab - free, but often not open - Different resources centered around important societal issues. Possibly useful in arts & humanities, or social sciences, but does not have a direct education focus, and often does not have an open license

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• Consortium for the Advancement of Undergraduate Statistics Education (CAUSE) - Depends on resource -  Search engine for statistics resources. Website contains many different types of resources, also non-educational ones, which confuses the formatting. Also has a number of dead links

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• Hathi Trust Digital Library - Public Domain, but sometimes unclear - Database with historical documents on research and academic fields. Quite unclear what direct goal it serves besides archiving, and educational purpose seems minimal
• Amser - Unclear (free, but also copyrighted) - Applied math and science search engine. The website is quick, but lacks clear license information or nicely formatted metadata. The resources can also be copyrighted
• Observer/Copernicus - Free, and open to use - Database of studies and actual data from the EU's Copernicus program, which is all about monitoring Earth from space. May be interesting for geo sciences & astronomy students. Specific license is unclear, but as a governmental product, likely public domain