ODaF is dedicated to the adoption of global metadata standards for the development and use of open-source statistical data to support research, policy making, and transparency.
re3data.org (Registry of Research Data Repositories) was funded by the German Research Foundation DFG in the period from 2012 to 2014 to promote a culture of sharing, increased access, and better visibility of the research data from repositories such as the ones below.
Springer Nature Data Services compiled a list of open source data grouped by subject.
The Open Definition states: "A piece of data is open if anyone is free to use, reuse and redistribute it -- subject only, at most, to the requirement to attribute and/or share-alike."
Data.gov - Data, tools, and resources to conduct research, develop web and mobile applications, design data visualizations, and more.