Documentary-Drama films of the silent era:
Chang: A Drama in the Wilderness (1927)
In the Land of the Head Hunters (1915)
In the Land of the War Canoes (1914)
The Silent Enemy (1930)

Collections and boxsets that include silent era documentary films:
The American Indian: Before the White Man (1914-1972)
Dziga Vertov: The Man with the Movie Camera
and Other Newly-Restored Works (1924-1934)
Great Old Short Subjects (1925-1938)
Saved from the Flames: 54 Rare and Restored Films (1896-1944)
Science is Fiction: The Films of Jean Painlevé (1910-1978)
Silent Era Studio Tours (1915-1925)
The Thanhouser Collection, DVD Volumes 10, 11 & 12 (1910-1916)
World War I Films of the Silent Era (1916-1917)