data.world is a data social network and search engine designed to accelerate and enhance data science by improving decision-making, knowledge transfer, and problem-solving. It is a community where communication and collaboration adds context to data. data.world is free to use, but registration is required.
DDE is a Department of Energy repository for datasets from DOE sponsored research. Its contents include numeric data, computer simulations, figures and plots, interactive maps, multimedia, and scientific images The repository can be searched by keywords or browsed by title, content type, DOE data center, DOE user facilty, host Website, sponsor, or subject category.
Covering many academic disciplines, r3data.org is a global registry of research data repositories. Each repository record includes the name of the repository, its URL, a description, subjects covered, content types, keywords, language, service provider, institutions, terms, and standards. r3data.org can be searched, or browsed by subject, content type, or country.