I suppose reflecting the steady decline in religiousness, the names which have almost vanished are the biblical ones. Until the 1900s, apart from everyday names like William, Henry, Richard and Robert, most ordinary people turned to the bible when they had used up their usual family names. Biblical names of disciples - Thomas, John, James, Mark, Luke - have always been fairly popular, but we no longer see Zacharias, Ezekiel, Enoch, Jehosaphat. Elizabeth, Anne, Rachel, Sarah are still around, but Ruth is not as common now. One of the families in the parish I am working on now seems hooked on Dionysius, which isn't even biblical as far as I know.
One name which has come and gone is Wendy. I think it was invented for Peter Pan, but I haven't seen many recently.
But as well as fluctuations in popularity, there has always been a 'class' dimension, where ordinary working people used a small set of names like John, Tom, Bill, Sam, Fred, while those in a layer above tended towards Edward, Richard, Roger, George; while higher up we got Archibald, Reginald, Clarence and Marmaduke. Of course when the film industry got started everything changed.