Kit & Ruthie 1934 resourceful girls growing up during the Great Depression
Welcome to Kit's World, 1934 : Growing Up During America's Great Depression (The American Girls Collection)
-Kit learns a lesson: a school story by Valerie Tripp
-Kit’s surprise: A Christmas story by Valerie Tripp
-Meet Kit, an American girl by Valerie Tripp
-Happy Birthday Kit: a springtime story by Valerie Tripp
-Changes for Kit: a winter story by Valerie Tripp
-Midnight in Lonesome Hollow: a Kit mystery by Kathleen Ernst
-Kit saves the day: a summer story by Valerie Tripp

Molly & Emily 1944 patriotic girls from the World War II era
-Molly marches on
-Brave Emily by Valerie Trip
-A spy on the home front: a Molly mystery by Alison Hart
Molly: An American Girl on the Home Front

Julie and Ivy 1974 optimistic girls in times of change
-Changes for Julie by Megan McDonald
-Happy New Year by Megan McDonald
-Julie's journey by Megan McDonald
-Julie and the eagles by Megan McDonald
Meet Julie (American Girl (Quality))by Megan McDonald
-Julie tells her story by Megan McDonald

Note: All American Girl books are from my personal library.