Inter-University Consortium For Political and Social Research (ICPSR) is the world's largest archive of social science data. International in focus but majority of the data is American.
Data Liberation Initiative (DLI) provides access to Statistics Canada microdata for research. Access through:
- ODESI at Scholar's Portal (recommended for currency and ease of use).
- Equinox (contact firstname.lastname@example.org for help downloading)
International Household Survey Network survey catalog has links to international household economic and social surveys, primarily on developing countries.
Global Barometer Surveys - regional political and public opinion surveys conducted in Asia, Latin America, Africa and Arab countries.
World Values Survey - a global survey of attitudes and values.
For more sources of microdata, see the vast list contained in the Microdata For Analysis Research Guide.