Zandalar Illusionist's Robe

Zandalar Illusionist Robes are cloth chest armor useable only by Mages with intellect and stamina. It also increases damage and healing done by spells, and increases spell hit chance. The robe is part of the armor set called the Illusionist's Attire.

Source
The robe is a reward for the quest given by Al'tabim the All-Seeing on Yojamba Isle in Stranglethorn Vale.