It's
Ginevra, not Ginerva, if you're thinking of the HP
Ginny.
You could use
Ginette,
Ginger,
Georgina,
Regina,
Virginia,
Genevieve,
Genevra or
Genista, or basically anything with ge- or gi- in it.
I'm currently adoring the sound of
Ginny (because of HP, of course), and if I have a daughter named
Jean, which is my #1 favourite for girls, she may well be nicknamed Jinnie as well as
Jeannie.
Winifred nn
Winnie is really cute, but I don't like the spelling Winny.