I would look at either biblical names as they are pretty much always classy or names popular in the 40s & 50s that haven’t really come back round yet...
I know young women aged 19-22 called Kathleen, Deborah, Helen, Rosalind & Elaine
All lovely names & very unusual in their age groups ...
What about Judith, Margaret, Blanche, Angela, Andrea, Jill, Gillian, Faye, Alison, Elspeth, Imogen, Jayne, Pamela, Juliet/Julie, Cassandra, Jennifer, Claire, Joanne, Caroline, Frances, Christine, Belinda, Louise, Mary, Marie, Patricia
John, Richard, Ian, Stuart, Eric, David, Scott, Neil, Gregory, Malcolm, Adrian, Gary, Neil, Anthony,