Links to some (but not all) of my Iowa grad school colleagues:
International Relations Links
ISA Compendium Datasets - A gathering of a large number of IR-related datasets by the International Studies Association and the work of Paul Hensel
Terrorism Studies Links
GTD - Global Terrorism Database at the University of Maryland’s (START) Center; currently the most comprehensive dataset on terrorist incidents
TOPs - Terrorist Organization Profiles Data at Maryland’s START Center
Global Administrative Areas - A dataset of lower-level political administration boundaries. Awesome for doing sub-state analyses.