These characters were seen in main character flashbacks. Below you can find each character in alphabetical order by their first name.
Jack's lover in Thailand.
Adam Rutherford was Shannon's father and Jack's patient.
A woman Sayid had once tortured.
Anthony is Locke's father.
Brian married Walt's mother and adopted Walt.
Bryan was Shannon's boyfriend.
Carmen is Hurley's mother.
Charles Widmore is a powerful man and the father of Desmond's girlfriend.
Eko went to see if a miracle occurred to bring Charlotte back to life.
Dave was Hurley's imaginary friend.
David is Hurley's father.
Dr. Brooks was Hurley's doctor at Santa Rosa Mental Institution.
Dr. Christian Shephard is Jack's dead father who appears both on and off the island.
A hitchhiker that Locke picked up.
Emily is Locke's biological mother who gave him up when he was too young to remember her.
Essam was Sayid's former roommate.
The man Sawyer wrongly believed to be responsible for the death of his parents.
Jack kissed Gabriela just before his wife told him she was leaving him.
Helen Norwood was Locke's love.
Isaac is a faith healer whom Bernard hired to heal Rose.
She was one of the leaders of the commune where Locke lived.
Jin lied to Mr. Paik and Sun, telling them his father was dead.
Jin never knew his mother.
Johnny is Hurley's buddy who worked alongside him at Mr. Clucks.
Charlotte Malkin's mother, Richard Malkin's wife.
Kevin was married to Kate.
Leonard was in the Santa Rosa Mental Institution and so was Locke's mom, Hurley, and Libby.
Liam is Charlie's older brother.
This person has ties to Hurley and Jack.
Lucy was the girl who almost changed Charlie's life.
We first saw this man in Charlie's flashback, then we saw him again in Hurley's flashback.
Marshal Mars' island connection is Kate Austen.
Matthew claims to be an attorney for Oceanic Airways.
Big Mike was the officer partnered with Ana-Lucia.
One of the leaders of the commune where Locke lived.
Mr. Paik is Sun's father and Jin's father-in-law.
A pawn shop owner who knew a lot about Desmond.
Nadia was Sayid's girlfriend.
Penny is Desmond's girlfriend.
Rachel is Juliet's sister.
Randy has connections with both Locke and Hurley.
Kate works for Farmer Ray before she is captured by the Marshal.
The doctor who convinced Juliet to work for him.
Sabrina is Shannon's wicked stepmother.
Sergeant Sam Austen is the man Kate believed to be her father.
Susan was Walt's mother who passed away before the plane crash.
Teresa Cortez was Ana-Lucia's police captain and her mother.
Thomas was Claire's boyfriend and the father of her child.
Tommy was Charlie's buddy.
Travis' wife dies after Jack's father operates on her while under the influence. Later we see Travis with Ana-Lucia.
A reporter who was doing a piece on Hurley.
Wayne was married to Kate's mother.
