This resource will help you identify nonprofit organizations.
If you are asked by the organization to locate similar nonprofits for benchmarking purposes. This a a useful resource.
You will need to register a free account to conduct effective searches.
The 990 forms will provide detailed financial data on nonprofit organizations.
Mintel is a good resource for marketing information and demographics.
A useful report is titled "Attitudes toward Charities and Non-profits - US - October 2016." This report has demographic information on donors and discuss why people donate to charities.