This is a close contender (it's is also up, and really thriving; it's even on close to the latest version): https://en.wikipedia.org/wiki/2b2t
I can recommend 2b2t if you don't mind the 4chan-like mentality in the chat. Probably the only server where coding is actually a desired, core skill in factions/teams/groups.
While yes 2b2t is on a modern version most of its history was spent on 1.12. Only last year did they jump to 1.9 and only in the last few months to 1.20. Not knocking it, just most of the old builds and metas were based on 1.12.
This is a close contender (it's is also up, and really thriving; it's even on close to the latest version): https://en.wikipedia.org/wiki/2b2t
I can recommend 2b2t if you don't mind the 4chan-like mentality in the chat. Probably the only server where coding is actually a desired, core skill in factions/teams/groups.