A few of mine —
A Grin Without a Cat [Chris Marker, 1977] The Battle of Chile [Patricio Guzmán, 1979] Harlan County U.S.A. [Barbara Kopple, 1976] Lucia [Humberto Solás, 1968] Attica [Cinda Firestone, 1974] La Commune (Paris, 1871) [Peter Watkins, 2000]
Missing (1982) and Z (1969) by Costa-Gavras. Missing in particular is good to watch with lib parents.