Piper is a bright, musical name that entered the list in 1999, one year after the debut of the TV series Charmed, which featured a Piper, and it's been a consistent riser since. Piper Kerman is the memoirist whose prison experiences provided the basis for the hit Netflix series Orange is the New Black.

The e-addition takes the name from slightly hippie-ish nature name to the place name of a picturesque island off the coast of Scotland, and for baby namers it's by far the more popular spelling.

Most of the notable Rivers have been male, but this nature name certainly flows as well for a girl. The name River is still rising for both genders, with about 3500 baby boys receiving the name last year vs. 1900 baby girls.

Arya was derived from an Indo-Iranian word meaning "Aryan" or "noble." It is a masculine given name in Iran, Indonesia, Bali, and Sanskrit-speaking regions of India. In Hindu- and English-speaking parts of the world, Arya is more often a feminine name, the latter influenced by the similar Italian name Aria, meaning "air" or "song."

Sharp and spiky with international potential, as a feminine name, Nikita has its roots in Hindi, Marathi, and ultimately Sanskrit. It comes from niketa, meaning "home, habitation", and may also be spelled as Nikitha.

Mia, Gia, and now Sia!

Alexa was a steadily popular modern classic until Amazon's virtual assistant Alexa was released in 2013. It remains relatively well used in the US despite this, though its standing keeps dropping for obvious reasons. Too bad, because it's a strong and pretty name (which is probably why Amazon used it.)

While Skylar is currently the most popular spelling choice for girls, the Skyler option is more (statistically) unisex. Given to boy and girls in nearly equal numbers each year, it ranks around the middle of the US Top 1000.