https://en.wikipedia.org/wiki/List_of_think_tanks_in_the_United_States https://en.wikipedia.org/wiki/List_of_think_tanks_in_the_Uni... plenty of them are left-

https://en.wikipedia.org/wiki/List_of_think_tanks_in_the_United_States https://en.wikipedia.org/wiki/List_of_think_tanks_in_the_Uni... plenty of them are left-leaning. I'm not sure about the "dark money" bit though