There’s [name_u]Frankie[/name_u], which is cute, though I feel it works best for certain personalities of Miss [name_f]Francesca[/name_f]. You could just do Eska which sounds pretty on its own. On my list, I personally have [name_f]Effie[/name_f]. It’s really not much of a stretch.
Other options:
[name_f]Essie[/name_f]
[name_f]Chessie[/name_f]
Fresca
[name_f]Chi[/name_f] [name_f]Chi[/name_f]
[name_f]Chia[/name_f]
[name_u]Frannie[/name_u]