Very happy to find out that Maria Amalia has a new biography- after the first one published in 1932. It is not for sale but perhaps can be made available by request....
https://www.facebook.com/parmavpraze/photos/a.2020476721534278/2060250490890234/?type=3&theaterTo update the list (and explanations) posted earlier by Bravecoeur:
Maria Theresa - numerous biographies but nothing as comprehensive as Beales's masterful work on Joseph II
Franz Stephan - a few biographies but nothing in English
Maria Anna - half a book (life in Klangenfurt) + a publication on her and her convent
Joseph II - numerous biographies
Maria Christina - a few books in German
Maria Elisabeth - none (apart from articles and notes) + a publication on her convent
Maria Amalia - 1932 biography in Italian,
another one in 2018 (both not in German or English) Leopold - a few biographies in German*
Maria Carolina - early 20th century biographies in English (Acton, Bearne) + a few in German
Ferdinand - none (apart from articles and notes)**
Marie Antoinette - countless books
Maximilian - two biographies in German***
*There are numerous articles and specialised publications on Leopold, and also a few biographies in German, notably the two volumes by Adam Wandruszka (and as he reigned in Tuscany for so long, I am certain there are Italian biographies too but haven't checked):
Adam Wandruszka: Leopold II. Erzherzog von Österreich, Großherzog von Toskana, König von Ungarn und Böhmen, Römischer Kaiser, 2 Bände (Band I: 1747–1780, Band II: 1780–1792), Vienna, Munich 1963 and 1965.
Helga Peham: Leopold II. Herrscher mit weiser Hand. Styria, Graz u. a. 1987
** Have not found any biography as a book (there are certainly the articles in the volumes on MT's children and shorter biographical articles).
*** I checked. There are two German biographies on Maximilian Franz, both by the same author:
Max Braubach: Max Franz von Österreich, letzter Kurfürst und Fürstbischof von Münster. Versuch einer Biographie (etc.), Münster i. W.: Aschendorff, 1925
Max Braubach: Maria Theresias jüngster Sohn Max Franz. Letzter Kurfürst von Köln und Fürstbischof von Münster. Herold, Wien u. a. 1961.
Also there are number of special books on his role in certain political aspects in Münster and Colgne.