The staff of the National Archives Catalog has a bimonthly newsletter to which anyone can subscribe; a pop-up invitation appears just about every time you visit the basic Catalog search page at https://catalog.archives.gov.

Recent past issues of the newsletter are archived here: https://us11.campaign-archive.com/home/?u=bfeaf03e7b0b1636c0b375892&id=921cecd7dd.