Think tanks are policy research institutes that engage in policy research and analysis, and often advocate solutions. Many think tanks are non-profit organizations promoting social and economic justice and reforms, while others are funded institutes partisan in purpose providing solutions to the best interest of funding agencies, political parties and governments, etc.
The open web provides a plethora of resources for finding information about and from governmental and non-govermental organizations working to address issues surrounding your topic of research as well as grey literature.
What is grey literature?
Information published by entities (researchers or those working in the field) whose main purpose is NOT publishing (e.g. government and non-government organizations, think tanks, scholarly societies and associations, etc. Grey literature might be technical documentation, white papers, working papers, symposia, bulletins, unpublished works, technical reports, fact sheets, standards, patents and the like. Watch this video for more info.)
Why is grey literature important?
A large amount of public policy information is published as grey literature.
Below are a few advanced Google searching tips for find grey literature:
Image source: Kamei, F. et al., (2020) under a CC BY 4.0 license