Your criteria for exclusion seem quite flexible, so I am not sure if any of the following really count:
There are several works by holocaust and WWII survivors who are more notable for their post-war lives, e.g. Imre Kertesz, Marcel Reich-Ranicki, Inge Deutschkron. There are also works about victims of the war, e.g. about Tanya Savicheva.
1587 Year of no Significance has several biographies of people who were part of the upper levels of the Chinese state at the time, but the author's focus is more on the circumstances of their lives rather than on the individuals.
Wild Swans has a biography of the author's grandmother and her parents. The parents were not really nobodies, but not terribly important either (provincial CCP secretary or so, i.e. second tier after national leadership). But IIRC her grandmother had rather humble origins.
Some more soldier autobiographies: Josef Deifl, who fought in the Napoleonic wars, or Peter Hagendorf from the Thirty Years War.