Also related though maybe not resiliency-focused: It's quite easy now to download all of Wikipedia and all of Project Gutenberg to a hard drive, so that whatever problems you have in the post-apocalyptic hellscape, boredom won't be one of them.

Kiwix is the best software I have found for this and they make an extensive library of materials available for download themselves, which includes the aforementioned but also many other resources that would be helpful in a disaster scenario: https://library.kiwix.org/