INSCR Data Page (Center for Systemic Peace)
Freely available datasets include:
Forcibly Displaced Populations, 1964-2008 Major Episodes of Political Violence, 1946- Political Instability Task Force (PITF), State Failure Problem Set, 1955-
High Casualty Terrorist Bombings, 1989- Memberships in Conventional Intergovernmental Organisations (CIO), 1952-1997
Political Regime Characteristics and Transitions, 1800- (Polity IV Project)
Coups d'Etat, 1946-
State Fragility Index and Matrix, 1995-