Here’s a portion of the bluepost pertaining to the Classic Era realm clusters:
In descending order, the region/server type of these clusters are:
- PvP West
- Oceanic PvP
- PvE East
- PvE West
- PvP East 1
- PvP East 2
As others have stated, Whitemane (in PvP West) and Mankrik (in PvE East) receive free transfers from other clusters. I play on the PvP East 1 cluster holding together Benediction, Faerlina, Heartseeker, Incendius, and Netherwind. My advice is to roll a level 1 on a prospective realm/cluster and chat with the locals.