I like
Marguerite! I think it's a little old-fashioned but it still sounds 'fresh' enough to use. Plut, a
Marguerite nn
Margot would be awesome! (actually I'd prefer
Margo as a nickname for
Marguerite, because then it's just the Marg part with an o onn the end, but
Margot would work too.)
This name primarily makes me think of
Marguerite Henry.