Pretty much what it says.
You all know that I log tons of documentaries, many of them from public television and educational channels. I kinda pride myself on it, actually.
Anyway, many of these are available somewhere for free. Check out the PBS website, or Kanopy streaming which airs a lot of public television programs, or elsewhere that remains legal.
I'll try to keep this updated, but I wouldn't mind a call-out if there's a film that's more popular than I realized. This list is for the truly underseen and underappreciated. Suggestions welcome, but I won't add them unless I've seen them.