Kristen Kilar was played by Perrey Reeves, David Duchovny's at the time girlfriend.
Answers so far...
Darin Morgan - The Host (Flukeman) and Small
Potatoes (Eddie Van Blundht)
Gordon Baines - Our Town (staff physician) and Young At Heart (Dr. Ridley)
Nicholas Lea - Genderbender (Michael) and Sleepless (Alex Krycek)
Alex Diakun - Humbug (Curator), Jose Chung's "From Outer Space" (Dr Fingers) and Clyde Bruckman's Final Repose (Tarot Dealer)
Peter Lacroix - Ascension (Dwight), EBE (Ranheim/Frank Druce) and Unrequited (Nathaniel Teager)
Barry W Levy - Apocrypha (Navy Doctor) and Gethsemane (Dr Vitagliano) also Redux
John Piper Ferguson - F. Emascula (Torrence) and Christmas Carol (Det. Kresge) also Emily.
Chris Owens - Musings of a CSM (Yound CSM), Demons (Young CSM), Post Modern Prometheus (The Great Mutato), Agent Jeffrey Spender (Patient X/The Red and The Black/The End)
Name unknown - Red Museum(Beth Cane), Nisei/Momento Mori - Penny Northern
Name unknown - He was in the episode where frogs fell from the sky and he also played the sheriff or whatever in Chinga. I think that's it. Sorry for the lack of concrete info. :)
Name unknown - Coroner in "3" and Dr. Ivanov in "War of the coprophages"
Name unknown - "Die Hand Die Verletzt" as Mrs. Paddock and "Post Modern Prometheus" as the mad doctors wife.
Anwers received ...
Do you know any X Files trivia?