ER - 1994 Fevers of Unknown Origin 2-20 was released on: USA: 2 May 1996 Japan: 1 September 1997
Nurse - 1981 Fevers 2-17 was released on: USA: 7 May 1982
Of Unknown Origin - 1983 was released on: USA: 24 November 1983 Canada: 25 November 1983 Sweden: 10 August 1984 Denmark: 12 April 1985 West Germany: May 1986 (video premiere)
The Unknown - 2008 was released on: USA: December 2008
Edge of the Unknown - 2015 was released on: USA: 2015
Unknown - 1916 was released on: USA: 18 March 1916
The Unknown - 1913 I was released on: USA: 22 February 1913
Author Unknown - 2015 was released on: USA: 2015
The Unknown Eiffel - 1974 was released on: USA: 1974
Origin - 2007 was released on: USA: 1 December 2007
Origin - 2011 IV was released on: USA: 2011
The Unknown Ranger - 1920 was released on: USA: June 1920