Carl / ... (2 episodes, 2005-2008)
Walter Kubelik (2 episodes, 2000-2001)
Principal Greschner (2 episodes, 1998-1999)
Dr. Oberon Geiger (3 episodes, 1999-2000)
Londo Mollari (110 episodes, 1994-1998)
Brad (8 episodes, 1989-1990)
Yale Tobias (2 episodes, 1993-1994)
Doug Stanton (2 episodes, 1991)
Dr. Charles Alden (1 episode, 1985)
Leonard Brandon (1 episode, 1984)
Jack Denver / ... (2 episodes, 1983-1985)
Sid the Snitch / ... (25 episodes, 1982-1987)
George Alsop / ... (2 episodes, 1978-1979)
Dr. Simon Ward (1 episode, 1989)
Judah P. Benjamin 1 episode, 2017