Economic journals are a good source of data for your own projects. More and more journals are requiring that published authors post their data and code to the journal website. Journals with data requirements include the Journal of Political Economy and the Quarterly Journal of Economics and all journals published by the American Economic Association.
The American Economic Association also has a webpage to help you find national and international datasets.
The Abdul Latif Jameel Poverty Action Lab (J-PAL) Dataverse: https://dataverse.harvard.edu/dataverse/jpal