We’re researching a sibling name for [name_f]Ruth[/name_f]. We don’t know gender yet so baby boy and girl names welcome 
Not sure what style you prefer, so:
Religious:
[name_f]Esther[/name_f]
[name_f]Miriam[/name_f]
[name_m]Nathaniel[/name_m]
Religious-wise, I would have different feelings for Jewish vs Protestant–[name_f]Ruth[/name_f] as a Protestant name feels very Puritan to me, so I think it would be nice it with another Puritan-popular name like [name_f]Abigail[/name_f], [name_f]Hannah[/name_f], or [name_m]Ethan[/name_m].
Old Fashioned Revival Name:
[name_u]Evelyn[/name_u]
[name_f]Helen[/name_f]
[name_f]Zora[/name_f]
[name_f]Margaret[/name_f]
[name_m]Clarence[/name_m]
[name_m]Leonard[/name_m]
[name_m]Edwin[/name_m]
Short (some of these are also religious, granted):
[name_f]Kate[/name_f]
[name_f]Mary[/name_f]
[name_f]Anna[/name_f]
[name_f]Cleo[/name_f]
[name_u]Owen[/name_u]
[name_m]Eli[/name_m]
Edit:
Some Ruth sibsets in my family:
Ruth, Harold, Joseph, Seth, and Richard (his first name was legally Robert but everyone called him by his middle)–early 20th century American Jewish
Ruth, Mehetabel, Abraham, Abiel, Elizabeth, Adironum, and Nehemiah–late 18th century Puritan
[name_f]Faye[/name_f]
[name_f]Amelia[/name_f]
[name_f]Bethany[/name_f]
[name_f]Bridget[/name_f]
[name_f]Miriam[/name_f]
[name_f]Tabitha[/name_f]
[name_f]Cora[/name_f]
[name_f]Nora[/name_f]
[name_u]Penny[/name_u]
[name_f]Poppy[/name_f]
[name_f]Elise[/name_f]
[name_f]Daphne[/name_f]
[name_f]Vera[/name_f]
[name_f]Lila[/name_f]
[name_f]Gemma[/name_f]
[name_f]Georgia[/name_f]
[name_f]Charlotte[/name_f]
[name_f]Scarlett[/name_f]
[name_f]Lucy[/name_f]
[name_f]Corinne[/name_f]
[name_f]Paige[/name_f]
[name_f]Lydia[/name_f]
[name_f]Mae[/name_f]
[name_f]Heidi[/name_f]
[name_f]Naomi[/name_f]
[name_u]Blaire[/name_u]
[name_f]Eleanor[/name_f]
[name_u]Sydney[/name_u]
[name_f]Daisy[/name_f]
[name_f]Iris[/name_f]
[name_f]Ivy[/name_f]
[name_f]Sybil[/name_f]
[name_f]Felicity[/name_f]
[name_u]Cassidy[/name_u]
[name_f]Dahlia[/name_f] “[name_f]Dolly[/name_f]”
[name_f]Molly[/name_f]
[name_f]Ruth[/name_f] & [name_f]Nell[/name_f]
[name_f]Ruth[/name_f] & [name_f]Eve[/name_f]
[name_f]Ruth[/name_f] & [name_f]Clara[/name_f]
[name_f]Ruth[/name_f] & [name_f]Hazel[/name_f]
[name_f]Ruth[/name_f] & [name_f]Ida[/name_f]
[name_f]Ruth[/name_f] & [name_f]Ada[/name_f]
[name_f]Ruth[/name_f] & [name_f]Naomi[/name_f]
[name_f]Ruth[/name_f] & [name_f]Phoebe[/name_f]
[name_f]Ruth[/name_f] & [name_f]Martha[/name_f]
[name_f]Ruth[/name_f] & [name_f]Mabel[/name_f]
[name_f]Ruth[/name_f] & [name_f]Myra[/name_f]
[name_f]Ruth[/name_f] & [name_f]Mae[/name_f]
[name_f]Ruth[/name_f] & [name_f]Dorothy[/name_f]
[name_f]Ruth[/name_f] & [name_f]Lillian[/name_f]
[name_f]Ruth[/name_f] & [name_f]Mara[/name_f]
[name_f]Ruth[/name_f] & [name_u]Joan[/name_u]
[name_f]Ruth[/name_f] & [name_f]Cora[/name_f]
[name_f]Ruth[/name_f] & [name_u]August[/name_u]
[name_f]Ruth[/name_f] & [name_u]Emmett[/name_u]
[name_f]Ruth[/name_f] & [name_m]Silas[/name_m]
[name_f]Ruth[/name_f] & [name_m]Miles[/name_m]
[name_f]Ruth[/name_f] & [name_m]Ezra[/name_m]
[name_f]Ruth[/name_f] & [name_m]Ezekiel[/name_m]
[name_f]Ruth[/name_f] & [name_m]Abram[/name_m]
[name_f]Ruth[/name_f] & [name_m]Clark[/name_m]
[name_f]Ruth[/name_f] & [name_m]Arthur[/name_m]
[name_f]Ruth[/name_f] & [name_m]Lewis[/name_m]
[name_f]Ruth[/name_f] & [name_m]Tobias[/name_m]
Of the names suggested I like …
[name_f]Ruth[/name_f] and…
[name_m]Nathaniel[/name_m]
[name_m]Edwin[/name_m]
[name_f]Anna[/name_f]
[name_f]Nora[/name_f]
[name_f]Sybil[/name_f]
[name_f]Clara[/name_f]
[name_f]Phoebe[/name_f]
[name_u]Emmett[/name_u]
[name_m]Arthur[/name_m]
[name_m]Ezra[/name_m]
[name_f]Lydia[/name_f]
[name_f]Naomi[/name_f]
Other suggestions
[name_f]Rachel[/name_f]
[name_f]Claire[/name_f]
[name_f]Sarah[/name_f] ([name_f]Sara[/name_f])
[name_f]Margot[/name_f]
[name_f]Anne[/name_f]
[name_f]Anneliese[/name_f]
[name_f]Katherine[/name_f], [name_f]Catherine[/name_f]
[name_f]Johanna[/name_f], [name_f]Hannah[/name_f]
[name_f]Susannah[/name_f], [name_f]Susanna[/name_f]
[name_f]Rebecca[/name_f], [name_f]Rebekah[/name_f]
[name_f]Dorothea[/name_f]
[name_f]Antonia[/name_f]
[name_f]Annika[/name_f]
[name_f]Anastacia[/name_f]
[name_f]Linnea[/name_f]
[name_m]Edward[/name_m] ([name_m]Ned[/name_m], Ted)
[name_m]Edmond[/name_m], [name_m]Edmund[/name_m]
[name_m]Peter[/name_m]
[name_m]George[/name_m]
[name_m]Phillip[/name_m]
[name_m]Sebastian[/name_m]
[name_m]Robert[/name_m]
[name_f]Elena[/name_f]
[name_f]Ester[/name_f]
[name_f]Nancy[/name_f]
[name_f]Ella[/name_f]
[name_f]Ellen[/name_f]
[name_f]Lydia[/name_f]
[name_f]Amy[/name_f]
[name_m]Arthur[/name_m]
[name_u]Max[/name_u]
[name_m]Melvin[/name_m]