gonna need some hard drives lol. wikipedia is only about 100GB. annas archive is like 1PB, and even just the index is 1TB. the various government archives that were collected are at least 500TB (and probably closer to several PB).

other good things to mirror are probably open source code repos (they get taken down all the time - especially emulators, p2p, and now encryption), libretexts, linux repositories, 3d printed gun files, documentation, project gutenberg, the internet archive, openstreetmaps, the reddit archive, and any other content you find personally valuable - including websites and youtube videos.

the sum of this data is in the dozens to hundreds of petabytes, which is obviously infeasible so i personally try to curate what i find personally valuable and of highest societal value and risk, and to partially mirror what i can for the rest.