Rapture was a city that attracted the world's best and the brightest, or at least people who had come under the spell of Andrew Ryan's economic philosophy. There was a vast assortment of people who came to Rapture: from artists to scientists, from engineers to athletes. Below is a list of known citizens of Rapture who appeared in, or were mentioned in, BioShock.
Becky Langford - Someone of familiarity to Julie Langford, mentioned in the Audio Diary "The Lazarus Vector." Possibly her daughter or even her pet.
Charles - A character mentioned by the Lady Smith Splicers.
Coswell - A character mentioned by the Ducky Splicers, possibly a supervisor.
Epstein - one of Diane McClintock's comrades on Atlas' raid for ADAM. He was killed trying to get his hands on the Little Sister. He is also the possible owner of Epstein the Swami machines.
Faith Farthingworth - Died April 14, 1942. Daughter of Horace and Jennifer Farthingworth. Her name is found on the head stones in the Tea Garden (Date of death contradicts the creation of Rapture unless her grave was moved to the city after its construction).
Florida - A character mentioned by the Lady Smith Splicers, likely a servant.
Siegler - A character mentioned by the Dr. Grossman Splicers.
Sydney - A character mentioned by the Lady Smith Splicers.
Thomas - A character mentioned by the Lady Smith Splicers.
Valette - Along with Epstein and McGee, she has also passed away in their last raid for ADAM. It is possible that before the Big Daddy was killed, it was able to take them down first. The Audio Diary, "Today's Raid" is their report from Diane McClintock on their latest scavenge.
William - A character mentioned by the Lady Smith Splicers.