Project site: https://www.kiwix.org/en/

Links to content for download (or I guess you're able to within the app?) https://wiki.kiwix.org/wiki/Content_in_all_languages

Explanation of labels on files: https://download.kiwix.org/zim/README

Overview of content they offer for download: all of wikipedia (without audio or video, 83GB), gutenberg's public domain works (40,000+, 65GB), 167 stackexchange forums, various wikimedia projects (related to wikipedia: wikisource, wikinews, wikivoyage, wikihow, wikiversity, wikiquotes), and some other random forums (ubuntu or appropedia come to mind as listed), and others

They also have TED talks and Khan Academy videos, but I don't see why you couldn't just use something like youtube-dl to download specific ones you want (and this reminds me that I guess you could probably freely download and share such videos online with creative commons licenses)

(As relates to this win, I'm sure there's lots of political or religious content and primary sources that might be invaluable for research as well as a backup for education in the event of a natural or manmade disaster)