If anyone is wondering which characters they played:
-Jewel Staite played Amy pond in 7×03
-Amanda Tapping played Naomi in season 8.
-James Marsters and Charisma Carpenter played Don and Maggie Stark in 7×05
-Katie Cassidy played the first Ruby in season 3.
-Orlando Jones, John Barrowman and Stephen Amell were not in Supernatural and are just fans of the show:)