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)
Silent Era Studio Tours (1915-1925)
World War I Films of the Silent Era (1916-1917)