Server Population - Why don't we organise a massive movement to flesh out the other servers? We just need to do this a community. We don't need Blizzard. : r/classicwow
Classic WoW Realm Population Report - Data Aggregated Through Community - Wowhead News
WoW Private Server Population Report (2021-05-01, weekend) - over 90k concurrent, archived : r/wowservers