@liaizon @evan well... what I'm doing is using a list of servers that are currently up, and just getting nodeinfo for them, so I do have a list of *some* historical servers that are gone now, but I doubt it's anywhere near as good as Evan's data.
Someone who might have good data is @minoru who has been crawling the lists of federated servers for several years now to make https://nodes.fediverse.party/ (the list I use), and would have probably have a bunch of no-longer-reachable nodes in his database, including ones that were only known by nodes that are themselves no longer up, etc.