I have a small list in my head, of course
From #Kiwix library:– Wikipedia [EN]
– ArchWiki (good source of information about tips&tricks for software not only for ArchLinux users)
— To fix some hardware/software without the Internet:
+ iFixit library
+ Docs for foundations of Internet and it's services: C++/PHP/HTML/Perl/PostgreSQL/nginx/etc docs
+ StackOverflow parts (network engineering, ServerFault, programming, etc)
+ Source code? (at least to install something without the Internet on the some OS with compiler and some libs)
Some things which may be useful for other people:
– Project Gutenberg library parts (medicine, agriculture, usual literature (to read something without the network), philosophy)
– Public Domain Recipies and GrimGrains Recipies
– Flibusta archive. Without PDF and DJVU it weights near 1Tb. And I suppose, after removing all the cringe literature about fucking попаданцы — it will weight lesser
— Some guides about plumbing, woodworking, soldering etc — also to fix something. I have a printed book about how to service house, from near 1998 — still using it, lol
— ISOs for some Linux/BSD distributions
All of these obviously not for one user, but for sharing on necessity, like it was at 199x