I routinely employ all of these (as do most IR and Comparative Political Scientists and many economists). It’s nice to have a place to keep all of them.
Governance
- INSCR – Home of the famous PolityIV data
- Freedom in the World - Freedom House Data, dumped to Country-Year CSV here
- Economist Intelligence Unit - Publishers of the biannual Democracy Index, dumped to CSV here
- CSCW – Curators of Vanhanen’s Polyarchy data
- Archigos – A Dataset of State Executives
- Failed States Index - A collaboration between Foreign Policy and the Fund for Peace, dumped to CSV here
Warfare
- Correlates of War - Practically self-explanatory
- Polities at War – A Dyad-year dataset for every observed case of two nations at war in a given year. A Merger of the Polity IV data with the Correlates of War Militarized Interstate Disputes Dyadic dataset.
Economic
- World Bank Data Catalog – Home of the impressive (though tough to refactor into useful shape) World Development Indicators, dumped to individual Country-Year CSVs here
Socio-Demographic
- US Census Bureau – Also a no-brainer
- General Social Survey – The finger on the annual pulse of America
Geographic
- ESRI Data – Makers of ArcGIS
- US Census Bureau – The TIGER dataset for the United States