Federal Reserve Bank of St. Louis · Market & fundamentals data
In-depth entry
Free economic database from the St. Louis Fed aggregating hundreds of thousands of US and international time series, with graphs, vintages (ALFRED), an Excel add-in and a keyed JSON/XML API
Statistics Canada (Government of Canada) · Open & public data
In-depth entry
Canada's national statistical agency publishing census, economic and social data tables with open licensing and programmatic access via Web Data Service
The Wharton School, University of Pennsylvania · Market & fundamentals data
In-depth entry
Institution-subscribed research data platform from Wharton hosting CRSP, Compustat, TAQ, OptionMetrics and dozens of other vendors' databases with web queries, SQL, SAS, Python and R access