Gustave Vertunni included several queens among his figures, mostly French, but still, several of those ladies had important roles to play in European events. There are currently several auctions up on eBay featuring these figures.
Vertunni also produced a figure of the Empress of Austria, Maria Theresia. I think I've seen figures of the Tsarina Elisabeth, who ruled Russia through half of the Seven Years' War, as well as of Madame Pompadour, Louis XV's mistress, who had an influence on French foreign policy of the time.
CBG-Mignot also included some famous and notable ladies in its catalog (and in the catalogs of the companies that merged to form the present-day Mignot). They, too, can be found on eBay and elsewhere on the secondary market.
As others have mentioned, Henry VIII's wives have been brought out by several manufacturers.
Back in the day, Rose Miniatures (Russell Gammage) produced a figure of the ancient British tribal queen Boudicca. I think he also had a figure of Cleopatra in his catalog. He also produced a figure of Queen Charlotte, George III's consort. She's most notable for producing heirs, I suppose, than for anything else, but the Georgians did like to hold the King and Queen up as an ideal of the nation's family, even if the truth was more mundane.
There are a number of figures available of Britain's most famous Queens, too--Elizabeth I (notably Stadden/Tradition), Victoria and Elizabeth II. Stadden produced a vignette of Elizabeth and Raleigh on a single base, depicting the legend in which Sir Walter spread his cloak over a puddle that the Queen might pass with dry feet (as true as Pastor Weem's Washington and the cherry tree).
Speaking of Washington, Imrie-Risley have a figure of Martha Washington in their catalog. It's a kit, so you'd have to paint it or get it painted. But it's currently available, and she's certainly an important figure in our history.
I also remember a series of figures depicting famous Irish people. The figures were sold as souvenirs in Ireland. The series included at least one woman, but her name escapes me. A friend of mine is of Irish descent and brought the figure back from a trip to Ireland, and asked me to paint it. I think she led a rebellion against the English in the 18th century, but I can't now remember.
Anyway, those are all suggestions that come to mind. Good luck in your search!
Prost!
Brad