These are not researchers, but some major people and outlets who comment on politics and policy, mainly in the US but also worldwide. Likely, they are covering some of the policy areas you are interested in. They are also some of the best aggregators of new ideas. 

In random order: Washington Monthly, Vox (including Ezra Klein, Matt Yglesias), Andrew SullivanNew Republic, Kevin Drum/Mother Jones, Atlantic MonthlyTyler Cowen, The American Interest, Slate, Jonathan Chait/NY Magazine, Brad De Long, FiveThirtyEight and the New America Foundation. The search page also covers the outlets which Matt Yglesias and Ezra Klein previously wrote for. 

Nominations for additions, from across the political spectrum, accepted here.