Energy

Ethereal

The space between the inner planes is the Ethereal plane and it overlaps with the material and elemental planes.

Astral

All energy originates from the Astral plane, it flows through and creates the other planes. The source of magic flows somewhat like a cone, with the material planes inside it.

Shadow

Shadow space is not quite a plane but rather the absence of energy. It is infinite and endless.

Feywild, Shadowfell

These planes are the echos of the prime plane forming between the Astral and Shadow planes.