The CRSP (Center for Research in Security Prices) database provides acces to NYSE/AMEX/Nasdaq daily and monthly security prices and other historical data related to over 20,000 companies. It also includes daily and monthly US indices data from 1925 to the present.
CHASS (Computing in the Humanities and Social Sciences). CHASS is an online resource for teaching and research in social sciences hosted at the Faculty of Arts and Science, University of Toronto. The data is hosted and disseminated by CHASS. Each CHASS subscriber must have data agreements with the respective data providers to access the various datasets.