One of the best looking dragonriding customizations, the Renewed Proto-Drake: Embodiment of the Storm-Eater, was datamined in the beta but it was not clear how to get it. Obviously it was Raszageth related, but many people assumed it was similar to the Mythic-only mounts of previous expansions, but it turns out that isn’t the case!
Players have been receiving this customization from Raszageth on Normal mode, and even though it’s pretty rare, there are quite a few out there now.
Here are a few extra images of the drake: