In England, especially Devon and Cornwall, the name Wilmot (described on BtN as masculine only) was heavily used for girls until well into modern times. It seems like an English version of Wilma that may work for parents wanting to name a daughter after a William but reject Wilma and Wilhelmina.
Wilma was a regular in the American top 1,000 from the 1880s to the 1960s with its peak in 1920 (68th position), but nowadays conjures up old ladies (not to mention one of the Flintstones characters). It is not the case in Sweden, however, as there it is one of the top 10 girls' names and the pronunciation of the initial letter there is in this case like a 'v'.