http://www.propublica.org/

ProPublica is an independent, non-profit newsroom that produces investigative journalism in the public interest.

Nonprofit Explorer

https://projects.propublica.org/nonprofits/

Use this database to search over 1.8 million tax returns from tax-exempt organizations and see financial details such as their executive compensation and revenue and expenses. You can browse raw IRS data released since 2013 and access over 8.3 million tax filing documents going back as far as 2001.