Elizabeth is the ultimate classic, timeless girls name.
Otherwise I would think of names which have been in use for a long time e.g. medieval and Tudor names: Isabella and Isabel, Eleanor, Catherine/Katharine, Philippa, Bridget, Jane, Margaret, Matilda, Alice, Cecily, Amy, Frances, Anne, Dorothy and Emma. Some are currently popular, others less so.
There's also biblical names like Hannah, Sarah, Mary, Rebecca, Lydia, Leah, Susannah, Esther and Rachel.
Then there's names I associate with the post Tudor era like Caroline, Charlotte, Louisa, Georgiana, Sophia/Sophie, Harriet, Victoria, Henrietta and Marianne.
Plus classical and literary names like Cassandra, Helen, Rosalind, Penelope and Juliet.