I wanted to suggest site:old.reddit.com since I use that version with automatic redirect, but this:
https://old.reddit.com/robots.txt
is very different from this:
https://reddit.com/robots.txt
I guess there is a market for search engine (maybe accessed through tor) which does not care about robots.txt, DMCAs, right to be forgotten etc. Bootstrapping it should not be that hard since it can also provide better results for some queries since nobody is fighting about the position until it's widely known.
I'm not sure how far are we from being able to do full text internet search. Or rather even quote search, preferably some fuzziness options. That would be cool, Google's quotation marks were really neat back when they were working.