And they never made a faithful film of the sequel to The Wizard of Oz, because that's a transgender story too.
No, its not. It's a loose allegorical political fable about the Progressive/Populist Era. The author, L. Frank Baum also designed some of the first department store window displays, edited the first trade magzine for designers and wrote the first text on the subject, The Art of Decorating Dry Goods Windows and Interiors (1900) . He was a very strong supporter of women's suffrage, and wrote several stories of girls defying traditional gender roles. The real sequal to TWWoO had a feminist revoloution and promoted gender equity long before any such thoughts were popular.
As for follow ups, he only wrote 13 more Oz books and lots of Oz based short stories.
The Wonderful Wizard of Oz (1900)
The Marvelous Land of Oz (1904)
Queer Visitors from the Marvelous Land of Oz (1905, comic strip depicting 27 stories)
The Woggle-Bug Book (1905)
Ozma of Oz (1907)
Dorothy and the Wizard in Oz (1908)
The Road to Oz (1909)
The Emerald City of Oz (1910)
The Patchwork Girl of Oz (1913)
Little Wizard Stories of Oz (1913, collection of 6 short stories)
Tik-Tok of Oz (1914)
The Scarecrow of Oz (1915)
Rinkitink in Oz (1916)
The Lost Princess of Oz (1917)
The Tin Woodman of Oz (1918)
The Magic of Oz (1919, posthumously published)
Glinda of Oz (1920, posthumously published)