The name of a monstrous wolf in Norse legend, who kills the god Odin and is then killed himself by one of Odin’s sons. Harry Potter author J.K. Rowling used the name for one of her most terrifying characters: the evil werewolf Fenrir Greyback.

A royal name in Spain, Felipe could make a lively alternative to the English sounding Philip. It has ranked on the US Top 1000 almost every year since the beginning of the twentieth century, but has never risen above the Top 300, making it a familiar without being overused.

Captivating and gorgeous, powerful but with gentle sounds, Fatima is a popular name of Arabic origin. In the Quran, she is one of the Prophet Muhammad's daughters, and the wife of Ali, the forth ruler of the Muslim world. Fatima is regarded as the ideal example of a Muslim women, which makes it a favorite among Muslim parents.

As a member of two trendy name categories, animal and occupational, this name broke into the Top 1000 in 2004 and would make a nice tribute to an angler Grandpa.

Another old-school nickname getting new attention thanks to TV's Mad Men. Names like Fred, Pete, and George have been out so long it's time for them to come back in. It reentered the US Top 1000 in 2015 following a two-year absence from the list. It currently ranks Number 199 in England and Wales.

Not only are individual flower names more popular (and out-there) than ever, but so too are the more generic names like Florence and Flora. While brother name Fiorello became known via long-term New York Mayor LaGuardia, the lovely Fiorella has never crossed cultures. She could join Arabella as a post-Isabella ella choice.

Francie is one of the most neglected nicknames for Frances, despite having more style value than Franny and Fanny and being more unique than Frankie. We'd love to see it get more use, whether as a Frances short form or as an independent name.

Where have all the Freds gone? We haven't seen many since the days of Flintstone and Munster. But it could be time for a comeback--if you think more of the sophistication of Fred Astaire, and of other nice guy names like Jack and Charlie and Sam.

This yellow harbinger spring bloom was named for Scottish botanist William Forsyth, and is even more unusual than such species as Acacia and Azalea.

Actor Farley Granger set it in motion, now could be a gentler alternative to Harley.

Ferdinand is a traditional name among Spanish royal families and also appears in Shakespeare's The Tempest, borne by the handsome young prince shipwrecked on Prospero's island. Bold, daring, and poetic, it was a popular choice in the US in the 19th and early 20th century, but the 1938 movie Ferdinand the Bull has left it with a lingering clunkiness and it has been out of style since the 80s.

A lacy, lucky name very popular in the Hispanic community a decade ago, less so now.

Fernanda is very popular in the Latino community, with a lot more charm than its male counterpart. The standard nickname is Nanda, and variations include Ferdinanda and Fernandina.

Long before the vogue of using Irish surnames for girls, writer Flannery O'Connor gave this one some visibility. It has a warm (flannelly) feel and the currently popular three-syllable ee-ending sound.

A name with several distinguished namesakes: the wife of ancient Roman Emperor Marcus Aurelius, a famous Italian opera singer, and two Catholic saints--making it both substantial and unusual.

The dynamic personality and paintings of Mexican artist Frida Kahlo have inspired growing numbers of parents to resurrect this form of the name. It does much better in certain European countries, especially in Denmark and Norway. The Frieda and Freida spellings were more popular in the US until the middle of the 20th century.

Florin is one of the legion of names derived from the root word for flower, most of them like Flora and Florence used for girls. But the boys' form Florin is among the popular French names for boys, along with sister name Fleur for girls. There was a ninth century Swiss St. Florin. The related Florian was the name of a second century Roman saint.

More unusual than Fiona and more user-friendly than Fionnuala, the engaging Scottish Fenella, has been scarcely heard in this country.

Fox is a fast-rising name for boys, initially popularized by the character Fox Mulder on The X Files, and recently resurged by the TV show's revival.

Finlo is a name from the Isle of Man, deriving from that island's pagan sun god, Lugh. Given the popularity of all Finn names right now, Finlo could be a great alternative for people who love the "Fin" sound but want a more unusual name.