Just like it says - female names with boyish nic-names or feminizations of boy's names.
Some examples of what I mean -
Dani -
DanicaDavie -
Davina Freddie -
FredericaHenry -
Henrietta Chris -
Chryseis Mel -
Melantha Mel,
Andy - Melangell
Jerry - Jeraldeen
Eddie,
Ed - Edalynne
What are your favs of these? Any others you can think of? I'm just curious to see what others come up with!