Great question!
The WoW Classic realms were made into clusters a few years back. Here are the relevant 6 clusters for NA:
Note that Deviate Delight and Grobbulus are not on that list, but are RPPVP servers, and are on their own, respectively.
From what some people have posted, the Mankrik PVE cluster, and the Whitemane PVP clusters are quite active. Deviate Delight has recently had a community-drive “Fresh” initiative and is presumably also relatively active.
There are some posts about Grobbulus guilds, each faction seems to have 1 raiding guild that raids weekends, and have been keeping the server going.
Ironforge.Pro has some info on population based on raid logs from a few weeks ago (apparently) that were uploaded to WarcraftLogs, so is unlikely to be a very accurate source for general activitiy.
https://ironforge.pro/population/era/?locale=US- [ERA] Grobbulus Alliance & Horde Need YOU
I was trying to find some of the more recent posts discussing populations. Someone posted about some activity cropping up on the Faerlina/Benediction cluster for example, but a quick scan through recent posts didn’t turn up a ton of links to add.
Anyway, good luck out there!
