I'm not a fan of the very popular Ella, Jack, Olivia, Oliver names but on the other hand I'm far LESS of a fan of monstrosities like Nevaeh-Rose, Sunshine-Spa'rkle or Jayden/Brayden/Kayden/Layden.
There are hundreds - probably thousands - of names which are underused but are perfectly normal. For example, in Scotland they publish lists of every first name given. There was only one girl registered with each of the following names:
Seraphina, Caroline, Candice, Lorraine, Linda, Olympia, Margarita, Kimberly, Judy, Kay, Gayle, Frederica, Evangelina, Julianna, Lucille, Nadine, Yvonne, Enid, Estelle, Patricia, Monica, Theresa, Tania, Shona, Sinead, Ursula, Dora, Diane, Daniella, Viviana, Sally, Rowena, Rhoda, Prudence, Persephone, Corrina, Pauline, Christine, Claudine, Blanca, Clementine, Adrianne.
Not all to my taste, but definitely tick the box of being a proper name, yet unpopular.