Well, one of my religious (not-legal) names is [name_f]Yosefa[/name_f], which is a feminine form of [name_m]Yosef[/name_m], which is translated to [name_m]Joseph[/name_m].
I’d say [name_f]Alexandra[/name_f], [name_f]Josephine[/name_f], [name_f]Michaela[/name_f], and [name_f]Gabriella[/name_f]/[name_f]Gabrielle[/name_f] are reasonably popular? [name_f]Jane[/name_f], [name_f]Johanna[/name_f], and [name_f]Louisa[/name_f] are all pretty classic. You could even argue that [name_f]Hannah[/name_f]/[name_f]Anne[/name_f] were originally feminizations, but the male form is, today, quite obscure and never really made the jump to English.
I prefer a feminized form to just calling a girl a boy’s name. Personal taste there. I also like old fashioned names.
I like some where I do NOT like the male name: I like [name_f]Caroline[/name_f], [name_f]Thomasin[/name_f]/[name_f]Tamasin[/name_f]/[name_f]Tamsin[/name_f], [name_f]Petra[/name_f], [name_u]Simone[/name_u], and [name_f]Theodora[/name_f] but dislike [name_m]Charles[/name_m]/[name_m]Carl[/name_m], [name_m]Thomas[/name_m], [name_m]Peter[/name_m], [name_m]Simon[/name_m], and [name_m]Theodore[/name_m].
Of ones where I like both male and female and both are known in English in any case, my favourites at the moment are probably: [name_f]Raphaela[/name_f], [name_f]Gillian[/name_f], [name_f]Alexandrina[/name_f], [name_f]Alastriona[/name_f], [name_f]Ramona[/name_f], and [name_f]Isidora[/name_f].
I can never decide how I feel about [name_f]Frances[/name_f]/[name_f]Francesca[/name_f].
I find [name_f]Henrietta[/name_f], [name_f]Harriet[/name_f], [name_f]Roberta[/name_f], [name_f]Louise[/name_f], and [name_f]Michelle[/name_f] unappetizing. (Though I like [name_m]Henry[/name_m] and [name_u]Michael[/name_u]).