With the latest Patch 10.2 Guardians of the Dream PTR build, 6 new mounts were added. These mounts show creatures seen in the Dragon Isles and the Emerald Dream, but they’re translucent!
These will be obtainable from Elianna at the Central Encampment in Amirdrassil, with a new currency called Dream Infusion. It is currently unknown how to obtain this currency, but you will learn how to obtain it by reaching Renown 5 with the Dream Wardens.