The book 'Inside Out & Back Again' by Thanhha Lai is an excellent example. It is about a young girl's experience as a refugee from Vietnam. It delves into the historical context of the Vietnam War and the challenges faced by Vietnamese people at that time. It is a story full of cultural elements and historical details that middle - grade readers can relate to.
There's 'The Birchbark House' by Louise Erdrich. This book is set in the 1800s and focuses on the life of an Ojibwa girl. It gives a great insight into Native American culture during that historical period. Also, 'Number the Stars' by Lois Lowry is set during World War II and shows the story of a Danish girl's involvement in helping Jews, presenting a different perspective on the war.
One great diverse middle grade historical fiction is 'Roll of Thunder, Hear My Cry' by Mildred D. Taylor. It deals with the African - American experience during the Great Depression. Another is 'Esperanza Rising' which tells the story of a Mexican - American girl during the Great Depression as well, showing different cultures and historical events.