I love
Libby too. She's so friendly and warm. But I only like it as a nn for
Elizabeth or even
Liberty, although like you I prefer
Elizabeth.
Hmmm. Another formal name?
Lilibet comes to mind, but of course that's just
Elizabeth in disguise.
Sibyl /
SibyllaBideliaWilhelmina -->
Billie -->
Libby? (pretty far fetched, I admit)
Cybele ("SIB-uh-lee")
BibigulLibed (means swan in Russian, "LEE-bet")
Libya (the country)