Association of Religion Data Archives (ARDA)
While its primary focus is on the United States, ARDA also has much comparative/international data on religion, including single-nation studies on topics such as spirituality and health, cross-national surveys on topics such as the role of religion in political life, and cross-national data on matters such as religious populations and measures of religious freedom.
Education Policy and Data Center
The Education Policy and Data Center provides access to education measures and indicators from a range of sources such as administrative records, household surveys, and assessment tests. Users can search for data by country, topic, or level of education.
Gender Equality Data and Statistics
The World Bank's collection of gender-equality data is " a one-stop shop for gender information, catering to a wide range of users and providing data from a variety of sources." Amongst the resources here are collections of macro- and micro-level data on topics such as control of economic assets and financial inclusion and an extensive set of gender-themed indicators that can be downloaded in bulk or queried by country, year, and indicator.
Health, Nutrition and Population Data and Statistics
HealthStats is "the World Bank’s comprehensive database of Health, Nutrition and Population (HNP) statistics," covering topics such as reproductive health, population growth, communicable and non-communicable diseases, and health facilities. The data are accessible through various means, such as via an interface that allows for both queries and bulk downloads and via tools to break health data down by household wealth.
World Bank Poverty and Equity Data
The World Bank has brought together a variety of datasets pertaining to the study of poverty, income inequality, and income distribution, along with other resources relevant for international development and economics. The many potentially-useful resources listed within this site include the World Income Inequality Database and PovcalNet. The site is part of the Bank's broader collection of poverty indicators. Other data resources are available via the Bank's "Poverty and Inequality" research program. Be warned - the World Bank tends to change addresses for websites without warning.