We love to hear from volunteers about what they are interested in transcribing (fill out the questions about future campaigns in our survey if you haven't already!) so feel free to email us (email@example.com) or submit a thread here on History Hub if there are Library of Congress collections you are particularly interested in. We are limited by what has already been digitized on loc.gov and what would make a good candidate for transcription (ie. no existing OCR or easily available printed edition, no copyright concerns). It sounds like you're interested in materials from the 20th century-and we're trying to work more of those items into the mix for future campaigns so stay tuned.
If you're looking to transcribe collections with particular topics that we don't cover, you should also check out what the Smithsonian Transcription Center and the National Archives Citizen Archivist programs are offering at any given point in time. For instance, right now Smithsonian offers more on science, art, and the African-American civil rights struggle than we do. And National Archives is running several series focused on military history. We love collaborating with those folks and are happy to recommend their programs to everyone. It's a great way to broaden your scope of transcription activities and to learn about other collections!
By the People Community Manager