We’ve datamined all the different Priest Tier set appearances for Dragonflight Season 1. The Mythic and PvP Elite sets have special animations and effects!
Priest Tier Set Transmogs from Vault of the Incarnate Raid
Priest Tier Set Transmog from Mythic Mode
The Mythic Priest tier set transmog has special lightning and flame effects attached to the Helm and Shoulder pieces! You can see these effects in the video below.