Here is a literature map with suggestions for authors similar to Naomi Novik.
Another suggestion : Mary Robinette Kowal
Kowal's latest is a dazzling alternative history set during the Great War. In the summer of 1916, American heiress Ginger Stuyvesant is engaged to British intelligence officer Benjamin Hartshorne and working in France as a medium in the top secret Spirit Corps, a force that gathers intelligence from fallen soldiers at the moment of death. It is grisly, exhausting work that puts the souls of the mediums in danger of becoming permanently separated from their physical forms, and it is made more dangerous by the discovery that the German army is not only aware of the Spirit Corps but has a double agent assisting them. When Ben is murdered, it falls to Ginger to help him move on by finding his killer and discovering the traitor in the corps while keeping her soul intact. Romance, action, and intrigue propel the plot from Kowal's compelling premise. Ginger's determination to do her duty in the face of lost love and senseless death and her eventual triumph will satisfy fans of Kowal's Glamourist Histories series as well as readers of Naomi Novik and Scott Westerfeld's Leviathan series.--Szwarek, Magan Copyright 2016 Booklist