Richilde

Rosela

Rosina

Rachilde

Raedburn

Ragnaillt

Regilinde

Richaut

Richelde

Rixa

Rogneide

Roheis

Rohese

Roscille

Rotrude

Sancha of Leon was an 11th century princess who became Queen of Spain after her brother was killed by Ferdinand I, whom she then married. A twisted tale indeed, but Sancha is one of those names that is both historic and extremely rare -- no babies were named Sancha or Sancho in the US in 2021. Sancho Panza was the sidekick of the fictional Don Quixote.

Sancha

The original but less common spelling of the ancient mythological name, now used mostly for fictional witches.   But the rise of the lovely Lady Sybil Crawley on television's Downton Abbey and the fall of the multiple personality Sybil, a self-confessed fake, may give Sibyl and Sybil more credibility as a name. 

Sibyl

Sibylle

Sigrid is a distinctly Scandinavian name that is starting to edge out into the wider world, a la cousin Ingrid. Unfortunately, short form Siri is now off the table, but Sigrid is still a possibility.

Sigrid

Sadb

Slani

Slynsy

Tangwystl

Temperence

Tescenda

Theidlindis

Theoderata

Thietburga

Medieval name that still hasn't crossed the ocean, known here primarily via actress/teacher Uta Hagen. 

Urracca

Willa has become increasingly fashionable, with its combination of Willa (born Wilella) Cather-like pioneer strength and the graceful beauty of the willow tree. 
Sophie Turner and Joe Jonas are the latest celebrities to welcome a daughter named Willa. Other stars who used this name include actress Keri Russell, who named her daughter Willa Lou and the late actor Philip Seymour Hoffman, who used Willa for the youngest of his three children. David Mamet and Brian De Palma also have daughters named Willa, plus it's the middle name of Meryl Streep's actress daughter Mary (called Mamie.) Young Willa characters have appears on Six Feet Under and True Blood.
 Willa originated as a short form of Wilhelmina. After a half-century hiatus, it reentered the U.S. Top 1000 in 2010 and soared to the Top 500, for the first time since 1949, in 2015. Willa might also work as an honor name for an ancestral William.

Willa

Waldrada

Wialdruth

Williswint

Wulfhilda

Zbyslava

Zytian

NerdyNamer's list "Unusual Female Names From My Genealogy R-Z" of 37 great name ideas: Richilde - Zytian!

Unusual Female Names From My Genealogy R-Z

Interesting and unusual names from the female side of my family tree from 602-1983. R-Z