As Modesty tells Tarrant in chapter 1 of Modesty Blaise: ‚Willie moves around quite a lot—he has a wonderfully varied list of girlfriends. From premier cru to honest vin du pays.‘
Some of the girlfriends are current, others remembered from his pre-Network days.
I list only the girls from the books and short stories. My source, John Higgins‘ Modesty Blaise site, also lists Willie’s girls from the comic strips.