Here’s a fun and informative website that is not just for California researchers, even though it is a part of the University of California system. “Calisphere” is loaded with interesting content in the form of primary sources—images and documents organized into subject areas or historical era.
Topics like “Everyday life” and “Popular culture”, along with “The Transcontinental Railroad” and “Japanese-American Relocation” are just a few of the interesting things to explore which could add perspective to a family history.
I also found a helpful guide to primary source analysis, intended to help history students but applicable to family historians:
Calisphere is worth a visit—I know I plan on spending some time there. I’d be interested in hearing what you find!