Rosalie is a beautiful name, but I know three, and two Rosas, and lots of Rosies. There were 147 Rosalies in 2020 and it’s rising.
Lyra and Freya are also both lovely, but popular.
how unusual do you want it to be OP? If I wanted a bit unusual I’d go outside of the top 500, actually unusual outside the top 1000, or wacky/out of fashion, outside the top 3000.
A bit unusual - Louisa, Celeste, Dahlia, Cassandra, Tessa
actually unusual- Elinor, Sierra, Cassia, Nuala, Mariella, Seraphina
wacky/out of fashion - Adrienne, Cicely, Devorah, Marian, Orianna, Augusta, Catriona, Celestine, Indira, Joelle, Rowena.