Eternal Traveler's Hearthstone
Source: Promotion. If you bought the epic edition of Shadowlands and can't find this in your Toy Box, go into Filter > Sources and see if 'Promotion' is ticked off.
The 
Eternal Traveler's Hearthstone is a toy hearthstone obtained from purchasing the Epic Edition of Shadowlands.
Guide awaiting review
Check Your Toy Box
If you purchased the Epic Edition of Shadowlands and cannot find the Eternal Traveler's Hearthstone in your Toy Box, open the Toy Box filter, navigate to Sources, and confirm that 'Promotion' is ticked on.
Use the Toy
When activated, your character takes on a ghostly, see-through appearance, raises their arms in a wide pose as a bright light forms in their hands, then begins to vaporize from the hands downward until fully gone, with the remaining light shooting straight up into the sky.
Free Up Inventory Space
This toy shares a cooldown with your regular 
Hearthstone, but you do not need the regular Hearthstone in your inventory for it to work, effectively freeing up one bag slot.
