Astral Plane

The Astral Plane, also known as the Astral Sea, is a plane of existence beyond the Material Plane. It is one of the boundary planes that lie between many of the other realms. It is an amorphous realm where the will and the imagination has influence over the surrounding space, where one can will oneself to float and move. Some creatures whose species have been there for a long time have learned to actually shape the amorphous matter and energy into structures and objects. They therefore tend to be very psychic-oriented.

Lady Allura told Vox Machina, during a conversation on how to dispose of the Horn of Orcus they had acquired, that when a Bag of Holding is destroyed, its contents jettison into the Astral Sea.

When Scanlan Shorthalt scried through his magical poo, his consciousness transcended the Material Plane, traveled across the Astral Sea, and arrived at his scrying destination on the Material Plane.

Creatures
Many beings reside within the Astral Sea, although Lady Allura only mentioned one:
 * Githyanki
 * Astral Dreadnought chained by Halas Lutagran
 * Erathis, the Law Bearer
 * Zehir, the Cloaked Serpent
 * Vokodo (formerly)