Sylvaine is nice! I think I like it better than Sylvia.
A couple we know just named their daughter Wilhelmina "Willa". I love it so much!
I have a soft spot for Nellie, so Nella is tempting, but I feel like it doesn't have enough gravitas. Helen is a bit stiff to me. What do you think of Helaine or Helenne? I like the French pronunciation, but I don't want to use accent marks in America. It would be too hard for people to understand.