Pamina. It's obscure but not supremely so, it's the name of the princess in Mozart's famous opera "The Magic Flute", but I have not met nor heard nor read of a single person with this name. I wish it gained some traction, even if that was just #900 in the Top 1000 or something. I'll take anything. I think Pamina is so pretty and sweet.
Also Kessie (not to be mistaken for
Kassie or
Cassie). It was the name of the baby bluebird Rabbit adopted and raised in an episode of The New Adventures of
Winnie The Pooh, and ever since then I've loved it. Haven't heard Kessie anywhere since.