Think tanks are institutions affiliated with universities, governments, advocacy groups, foundations, non-governmental organizations, and businesses that generate public policy research, analysis, and activity.
NGOs, or Non-Governmental Organizations, are non-profit organizations working on humanitarian, human rights, and sustainable development issues worldwide.
Being non-profit or even being humanitarian does not mean that an organization does not have a bias in favor or against a certain subject, industry or policy. Just because an organization has a bias does not mean that you would not use information from them.