As of now, a large number of WoW Classic characters have been created on the following realms. Players with characters on this realm are likely to experience severe queues at release.
Herod - PvP
Whitemane - PvP
We have updated the algorithm for the realm population tags so they more accurately reflect the expected population for that realm. The realms that are listed as “Full” are where we expect to see extended queues. If you’re concerned about long queue times affecting your play experience, you may want to consider creating characters on a lower population realm before the game releases on August 26 at 3:00 p.m. PDT.