In 2014, Sight & Sound polled 340 documentary critics, curators, academics and filmmakers asking for top 10 documentary lists. Over 1000 films got votes, from years as early as 1892 to as recent as 2013. This list is the combined critics and filmmakers list of all films that received 3 or more votes.
Source: http://www.bfi.org.uk/sight-sound-magazine/greatest-docs
Short films I have seen
https://letterboxd.com/david_crdza/list/sean-price-williams-legendary-top-1000-films/
Sight and Sound's The Greatest Documentaries of All Time
by maxwelldeuxVIP 8