Amiable, undiscovered geographic option. 

Aberdeen

Newly fashioned but familiar and with an on trend, unisex feel, Addison seems like the perfect solution for anyone who can’t decide between Madison, Adeline, and Alison. 
Addison really took off in the mid-2000’s, making a spectacular jump from being outside the Top 100, to being nearly within the Top 10, just two years later. Undoubtedly influenced by the introduction of Dr. Addison Shephard to “Grey’s Anatomy”, the name was at its peak in 2009. 
While it’s been steadily falling back down the charts, it does remain a popular choice. Currently given to nearly 4000 girls in the US each year, it ranks highly in New Zealand and Canada too. In the UK, it has made significant gains, becoming familiar for girls – and for boys too. 
Borrowed from an English surname, meaning “son of Adam,” Addison joined Madison as one of the few “son of” names to be used almost exclusively on girls. It also joins the 17 strong crowd of “Ad- names” in the charts for girls, including Adeline, Adelyn, and Adelaide. 
Contemporary and cool with a cute, sassy nickname, Addison has been a popular choice for celebrities. Baseball player Jason Bay, TV personality DeAnna Papas Stagliano, NASCAR driver Sam Hornish Jr, and Joe and Kendra Duggar all have daughters called Addison. 
It is unclear if Addison will fall as fast as it rose, but for now it remains comfortably within the Top 100. So, if love Addison but want your choice to stand out, you could try: Sullivan “Sunny”; Halliday “Hallie”; Barrett “Betty”; or Alcott “Lottie.”

Addison

Irish Aileen and Scottish Eileen may be pronounced the same way or Aileen can be pronounced with a long a at the beginning. While neither is particularly stylish, Aileen is slightly more popular and has reversed its downward slide to inch upward in the past few years, perhaps thanks to its stylish A beginning. Nicknames for Aileen include Isla, Ayla, Lee and Lena.

Aileen

Aoife, pronounced EE-fa, is derived from the Irish word aoibh, meaning "beauty." Aoife was borne by several different heroines of ancient Irish legend. In one tale, she was the fiercest woman warrior in the world and enemy of her twin sister, Scathach.
 
Aoife is very popular in Ireland, and is catching on across the UK as well. Aoife is sometimes Anglicized as Eva, but the names are from independent origins. Eva shares roots with Eabha and Aoibhe, both also currently popular in Ireland.

Aoife

Archambeau

Argyll

Brannigan

Callum, a charming Scottish name high on the list in England, Scotland and Northern Ireland, is rising through the ranks in the US now too. And it comes complete with the easy nickname Cal. Kyle MacLachlan chose Callum for his son. Callum might also be spelled Calum; in Ireland, the name became Colm, and in Scotland it's sometimes used as a pet form of Malcolm.
 
Callum was derived from Latin Columba, a unisex given name meaning "dove." Callum was popular among early Christians because the dove was a symbol of purity, peace and the Holy Spirit. St. Columba was one of the most influential of the early Celtic saints.

Callum

Evocative word name that's refreshingly straightforward.  Overtones of Christianity and penalty.  More subtle option: Cruz.

Cross

Caoife

Déaglán

Gustave

Iniya

This spelling, which came to the attention of readers of the best-selling Angela's Ashes as the name of author Frank McCourt's father and brother, the latter of whom wrote a bestseller of his own, lends the biblical name a more expansive, almost boisterous image. Malachy is one of the <a href="https://nameberry.com/baby-names/168/irish-names">Irish baby names</a> that manages to strike the golden mean between familiarity and distinctiveness.

Malachy is also the anglicized version of Melaghlin, one of St. Patrick's first companions. It was borne by the High King Malachy, who defeated the Vikings at the Battle of Tara in 980. St. Malachy was a reformer who reorganized the church in Ireland after the Viking raids.

Another origin, via a somewhat circuitous route, is from the surname Mac Seachnaill, "son of Seachnall", the Irish form of Secundus.

Irish actor Cillian Murphy has a son named Malachy.

Malachy

MacCrimmon

Naethen

O'neill

Rupert is a charming-yet-manly name long more popular in Britain (where it's attached to a beloved cartoon bear) than in the U.S. Yet we can see Rupert as a more stylish, modern way to honor an ancestral Robert.
 Rupert has been more visible in this country of late via Rupert Grint, portrayer of Harry Potter's Ron Weasley and the character Rupert Giles, mentor of Buffy in Buffy the Vampire Slayer, as well as actors Rupert Everett and Rupert Graves--not to mention media mogul Rupert Murdoch. 
 Off the US popularity lists since the early fifties, Rupert ranks high on Nameberry--at Number 170.

Rupert

Selvan

Sinaed

Thali

Viyan

Winthrop

Juliet M's list "Character names from the Eras series" of 23 great name ideas: Aberdeen - Winthrop!

Character names from the Eras series

If you want a mix of adorable, foreign, unusual, historic and downright weird in a baby names list, look no further. Lots of Irish and Scottish names, as that's where the books are mainly set.