I have just come across a fascinating book The Originals: Who's Really Who in Fiction by William Amos. It is an A-Z compendium of fictional characters with an explanation of the real people who inspired them. Some are quite well known, the biographical evolution of James Bond, for example, has been gone over often. Similarly Luthien in The Silmarillion, is well known as Tolkien's wife Edith.
Some sources of inspiration result in several literary figures. Lady Diana Cooper (wife of the politician Duff Cooper and one of The Coterie. ) was the basis of Mrs Algernon Stitch in Scoop and Officers and Gentlemen by Evelyn Waugh, as well as Lady Artemis Hooper in D H Lawrence's Aaron's Rod, Pauline Leonie in Nancy Mitford's Don't Tell Alfred, and Lady MacLean in Enid Bagnold's The Loved and the Envied, amongst other incarnations.
One of the most intrigue revelations in the book is that the original for Biggles. Air Commodore Cecil George Wigglesworth and the original for 'William', Richmal Crompton's brother John Lamburn, served together in the RAF during WWII. Amos speculates:
Unaware that it had the combined might of Biggles and William tucked away in Iceland, the War Office neglected to exploit the situation. Imagine the havoc that pair could have caused ...
The characters covered stretch from Shakespeare to the present day, but the majority are focused on the early part of the twentieth century, and if you are interested in the novel of this period then it really is a fascinating read.