Gladys Ewing Debutante Scrapbook (University of Houston Digital Library) is a new digital collection that includes invitations, notes, dance cards, and other items from 1911. Discovering American Women's History Online provides links to 19 additional digital collections with scrapbooks.
Two recent books provide historical overviews and specific examples of American scrapbooks:
WorldCat record with Google Books preview
In addition to an introduction to the history of scrapbooks, the 15 chapters in this book cover such topics as Willa Cather's childhood scrapbook and "Daily Life on South Carolina Plantation: A Scrapbook Memory of Three Generations of Women."
This volume includes color photographs of the pages from more than 200 scrapbooks.
Helfand and Rebecca Johnson Melvin discuss Scrapbooks and Self Works in a presentation at the Cooper-Hewitt Museum (YouTube, 1 hour, 38 min). Helfand includes examples from her book to illustrate the different ways in which women (and men) have used scrapbooks. After noting that scrapbooks are often overlooked as a research source, manuscripts librarian Rebecca Johnson Melvin describes numerous scrapbooks in Special Collections at the University of Delaware Library. Some of these scrapbooks are also featured in the Self Works exhibit that she curated.