I belong to GuideStar, an entity that "gather[s] and publicize[s] information about nonprofit organizations." They have been writing about smaller nonprofits facing automatic revocation of tax-exempt status. They inform the readers that there is a list of nonprofits at risk on the IRS Web site.
You might want to check your favorite charities. The more curious could search the PDFs by location or partial ZIP Code, or perhaps save and manipulate the downloadable Excel files.