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I believe the discords for certain BDO activities can answer this question. To find further information on this, search for a master list of BDO discords. Links for the entire community can be found in the official channel.
PA has no offical list.
For some reason Calpheon 2 is the unofficial RP server in NA.
Because of how RBF worked Velia is more PvP oriented than the other server clusters. Other than that, there really isn't anything set in stone as far as I can tell, unless some large guild has a "home server".