I have so far found the following. If anyone knows of any others, please get in touch. I am very keen to include women from all countries of the world - not just the UK, America, Canada, Australia, New Zealand, Newfoundland and so on - and would welcome your input. Many thanks.
BRITISH
Edith Bagnold (Great-grandmother to Samantha Cameron wife of the current British Prime Minister)
Maud Anna Bell
Vera Brittain (nursed in Malta, France and Britain)
May Wedderburn Cannan (VAD - Rouen, France 1915 and Paris in 1918)
Eva Dobble
Rosaleen Graves (nursed in Britain and in France)
I. Grindley
Winifred Holtby (drove ambulances in France)
Nina Mardel
Carola Oman
Jessie Pope (volunteered at St. Dunstan's home for soldiers who had been blinded which opened in 1915)
May Sinclair (Travelled to France with Dr. H. Monro in August 1914, May had to return to England after six weeks due to shell shock)
Millicent Sutherland - her work was painted by the French artist Victor Tardieu
Joan Thompson
Evelyn Underhill (I am not sure if she nursed but she did work for the SSAFA - Soldiers, Sailors, Air Force Association - a welfare group)
Alberta Vickridge
M. Winifred Wedgwood
Alice Williams (went to Paris to run a refugee centre)
AMERICAN
Mary Borden set up and funded a medical team and went to France 1915 - 1918
Mary H.J. Henderson lived in England and went with Elsa Inglis to Russia and Serbia to nurse
Marie Van Vorst
Edith Wharton
Ella Wheeler Wilcox - went to France in 1918 to read poetry and lecture to the troops
Grace Ellery Channing went as a War Correspondent
GERMAN
Henriette HARDENBERG - poet and nurse