This is just an update, as there have been some errors on the Connected Realms Support Page managed by Blizzard:
https://us.support.blizzard.com/en/help/article/14296
Argent Dawn is connected to The Scryers, and no others. If anyone has any information to the contrary, please let us know, so we can push for an update to the support page. Currently there are issues with other realms on the list that have (or had) mistakes listing incorrect connections, invalid names, etc.