[anthk]

9front a good bunch offline software repos from shithub can fit under a 4GB pendrive or DVD.

Not very usable to run current day stuff, but you have both netsurf, a video player, audio players, a PS/EPUB/PDF/image viewer, doc/xls readers to TXT (and converters) and Unix tools and games among 8/16 bit emulators.

With a bit of thinkering it can do a lot, look at the plan9 desktop page with 9front.

There's a Golang port too, and the AWK guide can be a godsend.

This is not for anuclear winter but maybe for an internet outage, which can be a real threat.