I'm very excited at this challenge, since I've found myself exploring a few forgotten authors already this year - Dunsany, Mirrlees, A E W Mason, Thesiger, Galsworthy. Also, I was at a stage where I needed some direction for my reading, so this couldn't be more timely. Below is my preliminary list, a mixture of authors who are new to me (Manning, Eddison) and those I've been meaning to pursue further. I'll add more if I have more time. The Eddison has recently been recommended to me by the same person who put me on the track of Dunsany and all I could remember was that the title had a worm in it.
Olivia Manning, The Balkan Trilogy and The Levant Trilogy
Freya Stark, A Winter in Arabia
Elizabeth Bowen, The House in Paris
E R Eddison, The Worm Ouroboros
W. Somerset Maugham, Cakes and Ale