US nonprofit sector

• Bolder Advocacy (on lobbying limits and 501c4 organizations)
• Giving USA 
  
• Independent Sector 
  
• How to Read a Form 990 (written by the Nonprofit Coordinating Committee) 
  
• Tax Exempt Organization Reference Chart (pdf)
  
• Guidestar 

International Nonprofit Sector

• CIVICUS 
• Charities Aid Foundation
• Guidestar International
• Interaction 
• International Center for Not-for-Profit Law

Affinity Groups and Associations for Grantmaking and Philanthropy

• Africa Grantmakers Affinity Group
• Africa Philanthropy Network
• African Philanthropy Forum
• Ariadne – European Funders for Social Change and Human Rights
• Asian Americans/Pacific Islanders in Philanthropy (AAPIP)
• Asociatia Pentru Relatii Comunitare (Romania)
• Assifero (Italy)
• Centro Mexicano para la Filantropia
• Community Foundations of Canada
• Community Foundations of the United Kingdom
• Comunalia (Mexico)
• Council of Michigan Foundations
• Council on Foundations (US)
• Donors and Foundations Networks in Europe
• East Africa Association of Grantmakers
• EDGE Funders Alliance for global equity
• Elevate Children Funders Group
• European Foundation Centre
• Forum of Regional Associations of Grantmakers (US)
• GIFE – Grupo de Institutos Fundações e Empresas (Brazil)
• Global Fund for Community Foundations
• Grantmakers Concerned with Immigrants and Refugees
• Grantmakers in Health
• Hispanics in Philanthropy
• Human Rights Funders Network
• Ibero-American Network of Community Foundations
• International Funders for Indigenous People
• Japan Center for International Exchange
• Network of Independent Funds for Social Justice (Brazil)
• Peace and Security Funders Group
• Philanthropy Australia
• Polish Donors Forum
• Russian Donors Forum
• SDGs Philanthropy Platform
• Worldwide Initiatives for Grantmaker Support