Definition of Open Access: Open Access (OA) describes online research publications that are free of all access restrictions (ex. pay firewalls) and free of most copyright or licensing restrictions on use. OA can apply to peer reviewed journal articles (and peer reviewed journals), conference papers, theses, book chapters, Ebooks, open textbooks, data sets, learning objects, or media made available through institutional repositories, open educational resource (OER) repositories, etc.
Amazon Web Services Public Data Sets 
"Public Datasets on AWS provides a centralized repository of public datasets that can be seamlessly integrated into AWS cloud-based applications. AWS is hosting the public datasets at no charge for the community, and like all AWS services, users pay only for the compute and storage they use for their own applications" (home page). Includes data sets for sciences, economics, geography, and general topics.
Data.gov
"The home of the U.S. government's open data. Here you will find data, tools, and resources to conduct research, develop web and mobile applications, design data visualizations, and more" (Home Page).
DataCite
"Locate, identify, and cite research data with the leading global provider of DOI's for research data" (home page). Includes re3data.org, Registry of Research Data Repositories.
Nature's Recommended Data Repositories
Nature provides a list of open data repositories for scientific research. They also provide suggestions to researchers who would like to submit their data to open repositories.
PLOS Recommended Repositories
The Public Library of Science (PLOS) has identified a set of repositories that are recognized and trusted within their research communities. Includes three data repositories for social sciences as well as STEM fields.
University of Minnesota Discipline-Based Data Archives
Includes excellent guide to managing your research data
"Public Datasets on AWS provides a centralized repository of public datasets that can be seamlessly integrated into AWS cloud-based applications. AWS is hosting the public datasets at no charge for the community, and like all AWS services, users pay only for the compute and storage they use for their own applications" (home page). Includes data sets for sciences, economics, geography, and general topics.
Data.gov
"The home of the U.S. government's open data. Here you will find data, tools, and resources to conduct research, develop web and mobile applications, design data visualizations, and more" (Home Page).
DataCite
"Locate, identify, and cite research data with the leading global provider of DOI's for research data" (home page). Includes re3data.org, Registry of Research Data Repositories.
Nature's Recommended Data Repositories
Nature provides a list of open data repositories for scientific research. They also provide suggestions to researchers who would like to submit their data to open repositories.
PLOS Recommended Repositories
The Public Library of Science (PLOS) has identified a set of repositories that are recognized and trusted within their research communities. Includes three data repositories for social sciences as well as STEM fields.
University of Minnesota Discipline-Based Data Archives
Includes excellent guide to managing your research data
Classroom Aid 
Directory of open source image sharing sites, museum repositories, music and sound repositories, and multimedia repositories.
The Directory of Open Access Repositories (OpenDOAR)
Authoritative directory of academic open access repositories. Search for a particular repository, or search the entire database of repositories for particular types of resources. Includes texts and media in all disciplines.
Directory of open source image sharing sites, museum repositories, music and sound repositories, and multimedia repositories.
The Directory of Open Access Repositories (OpenDOAR)
Authoritative directory of academic open access repositories. Search for a particular repository, or search the entire database of repositories for particular types of resources. Includes texts and media in all disciplines.
