One of the original unisex Irish surname names, energetic Casey bounced onto the scene in the 1960s, then peaked in the 1980s for both boys and girls. Today Casey is having a resurgence for both girls and boys and re-entered the charts on the girls' side, likely due to the character Kayce Dutton (pronounced like Casey) on the hit show Yellowstone.

Sky may be a bit hippie-ish, but it's bright and sunny nonetheless. Sky rejoined the Top 1000 in 2013 after spending many years off the list. Sky was the choice of magician David Copperfield for his daughter, born in 2010.

Vintage nickname for Roberta or Barbara, most famously borne by Roberta "Bobbie" in Edith Nesbit's classic The Railway Children. Bobbie is one of the adorable boyish nicknames newly fashionable for girls, with all the appeal of Billie but without the popularity (yet!).

Mamie is back. Having finally shorn her Mamie Eisenhower bangs, this insouciant and adorable nickname name is perfect if you want a zestier way to honor a beloved aunt Mary. Meryl Streep's actress daughter, properly named Mary Willa, is called Mamie Gummer. You might think of Mamie as a sister of the stylish Maisie.

The name of a courageous tribe, Cheyenne became quite popular in the 1990s, inspiring a wide range of spelling variations—Shyanne is one example that's still on the rise.

While for some, it may feel stuck in the shadow of the Dolly Parton song, Jolene re-entered the charts in 2010 and has seen increased use in recent years, ranking in the US Top 700 in the latest count. Tuneful and spirited, it combines the 'Jo' sound of Joanne, Josephine, and similar, with the lene suffix. As such, it could be said to share their meanings, "God is gracious" and "Jehovah increases".

Britney Spears' little sister Jamie Lynn was one of the first to put this nickname on the birth certificate. Cute for a child, but we recommend giving her the option of the full name for later use.

Less common than other virtue names, Liberty is nonetheless a name with a long American heritage.

With both the Dillon and Dylan spellings, usage of this gender-neutral names runs about ten to one boys to girls. But Dylan is used about 20 times as often as Dillon for both genders. Which might be a vote in favor of Dillon, though for better or worse, this spellings distances the name from singer Bob and poet Thomas.

Down to earth and versatile, Becky is a popular diminutive of the classic Biblical name, Rebecca. In the US, it was most popular as a stand alone name back in the 60s, while in the UK, it remained in the Top 300 right up until the early 2000s.

Made famous in fifties movies as a wholesome backwoods gal, Tammy was a Top 10 choice from the mid-60s to early-70s, but is now given to fewer than 100 babies per year in the US.

As this word is less often used to mean derriere, it becomes more possible to view Fanny as the kind of appealingly quaint nickname name, like Josie and Nellie, that many parents are favoring now.

Cady is one of those names that sounds popular but is actually rare in this form, given to only a few dozen baby girls in the US last year.

So uncool it's cool! Bertie makes for a boyish nickname for Alberta, Roberta, Bertille, Albertine... or just use it on its own, à la Billie or Frankie. Old school unisex nickname names are back in and Bertie has an undeniable vintage charm; particularly given soundalike Birdie rising in the ranks.

We usually think of place-names as a modern invention, but in fact Arizona ranked on the US Top 1000 from its inception in 1880 until 1911, when it vanished below the surface. It peaked at Number 510 in 1882, before Arizona became a state. One notorious vintage bearer: criminal "Ma" Barker, born Arizona Clark.

An early unisex nature name that has been surpassed by others, Dale is still a simple, sylvan and serene option.

Gertie has a certain homespun charm, summoning to mind butter-yellow braids and denim overalls, summoning mind the adorable character played by little Drew Barrymore in E.T. Is the world ready for the return of Gertie and Gertrude? Maybe?

With related choices such as Lark and Phoenix gaining popularity, why not Sparrow? Though it's usually thought of as a female name, Nicole Richie and Joel Madden chose it for their son.

Yet another creative character name from Toni Morrison, Denver was a daughter of Sethe's in the novel Beloved. Today Denver is most familiar as the name of the largest city in Colorado, used almost equally for girls and boys.

While some sources assign the place-name the romantic meaning "beautiful daughter of the stars," the Virginia region itself says the name is of uncertain Native American origin with many possible but no definitive meaning. No matter: Shenandoah is a lovely name that's rare but usable.