Blizzard has shared a cryptic teaser featuring what appears to Xal'atath, promising more to be revealed tomorrow, on August 6th! Although not explicitly stated what this reveal will be, it seems as though it will be a lead in to another series of animated shorts similar to Dragonflight Legacies and Shadowlands Afterlives.
The image doesn't give us a whole lot to go on. The markings heavily suggest the character is Xala'ath, though there are a few subtle differences in the markings, specifically above the brow crescent.
More obviously different is the bronze color hue, which also affects her eyes, suggesting the presence of some other light source or environment, rather than just a change in skin color.
Animated shorts have been made for every expansion since Mists of Pandaria's Burdens of Shaohao, featuring the trials of the last emperor of Pandaria in the days before the Great Sundering, and was the only series to launch mid-expansion, releasing ahead of Patch 5.4. Since then, the others were all featured as pre-release material.
Lords of War reintroduced (some of) the titular Warlords of Draenor as stories told by Vindicator Maraad to then-King Varian Wrynn, intended to help prepare him for a new war with the Iron Horde.
Harbingers told the backstories of three key figures in Legion's story ahead of the Burning Legion's second invasion of Azeroth — Gul'dan, Khadgar, and Illidan Stormrage.
Warbringers similarly introduced the story of Battle for Azeroth, exploring the lives of Jaina Proudmoore, Sylvanas Windrunner, and Queen Azshara.
Afterlives explored the characters and zones of each of the four covenants of the Shadowlands: Bastion, Maldraxxus, Ardenweald, and Revendreth.