I sorted the Guardian’s list for them:
Man with a Movie Camera, Dziga Vertov, 1929
Le Sang des Bêtes, Georges Franju, 1949
Night and Fog, Alain Resnais, 1955
Le Joli Mai, Chris Marker and Pierre Lhomme, 1963
Up series, Michael Apted, 1964
The War Game, Peter Watkins, 1965
The Hour of the Furnaces, Octavia Getino and Fernando e Solanas, 1968
Gimme Shelter, Albert and David Maysles, Charlotte Zwerin 1970
Primate, Frederick Wiseman, 1974
The Battle of Chile, Patricio Guzmán, 1975, 1976, 1979
Gates of Heaven, Errol Morris, 1978
Global Report, Peter Armstrong, 1981
Streetwise, Martin Bell, 1984
Shoah, Claude Lanzmann, 1985
Sherman’s March, Ross McElwee, 1986
The Thin Blue Line, Errol Morris, 1988
Close Up, Abbas Kiarostami, 1990
Loss Is to Be Expected, Ulrich Seidl, 1992
Pandora’s Box, Adam Curtis, 1992
Hoop Dreams, Steve James, 1994
China: Beyond the Clouds, Phil Agland, 1994
Salaam Cinema, Mohsen Makhmalbaf, 1995
Lessons of Darkness, Werner Herzog, 1995
When We Were Kings , Leon Gast, 1996
Little Dieter Needs to Fly, Werner Herzog, 1998
Buena Vista Social Club, Wim Wenders, 1999
The Gleaners and I, Agnès Varda, 2000
Bowling for Columbine, Michael Moore, 2002
The Five Obstructions, Lars von Trier and Jørgen Leth, 2003
Capturing the Friedmans, Andrew Jarecki, 2003
Aileen: Life and Death of a Serial Killer, Nick Broomfield And Joan Churchill, 2003
Some Kind of Monster, Joe Berlinger, Bruce Sinofsky, 2004
The 3 Rooms of Melancholia, Pirjo Honkasalo, 2004
The Power of Nightmares, Adam Curtis, 2004
Grizzly Man, Werner Herzog, 2005
Iraq in Fragments, James Longley, 2006
When the Levees Broke, Spike Lee, 2006
Sisters in Law, Kim Longinotto, 2006
Waltz With Bashir , Ari Folman, 2008
Man on Wire, James Marsh, 2008
Into Eternity, Michael Madsen, 2010
Five Broken Cameras, Emad Burnat, Guy Davidi, 2011
Pina, Wim Wenders, 2011
Stories We Tell, Sarah Polley, 2012
Solar Mamas, Jehane Noujaim and Mona Eldaief, 2012
The Queen of Versailles, Lauren Greenfield, 2012
Blackfish, Gabriela Cowperthwaite, 2013
Tales of the Grim Sleeper, Nick Broomfield, 2014
Virunga, Orlando von Einsiedel, 2014
Amy, Asif Kapadia, 2015