There is a hint of interest in the trend on boys however, suggested by Charlie’s steadily growing popularity on boys in the US.
Incidentally, Charlie is also becoming more popular on US girls, and could be considered unisex, but is still mostly male.
On Nameberry, I list some more vintage boy nicknames that have US potential.
My favorites are Louie and Marty–both seem wearable and imaginable on US boys and men. Go on over to Nameberry and share your favorites.