The names could literally be anything, because there was no rule linking secular to Hebrew/Yiddish/religious names. In addition to the ones Michele mentions, these are some names I've come across while transcribing:
Sari: Sarah, Chaya Sarah, Serl, Saraleh
Betti: Breindel, Beila, Buna
Ferencz: Peretz, Falk, Feivel
I recently came across a Jenő whose Hebrew name was Baruch. Why? Fortunately the record gave both the mother and the father's Hebrew names. The mother's father's Hebrew name was Baruch! So Jenő's Hebrew name was for his maternal grandfather!
Fort Collins, CO