The first preview of the 2.4.1 patch is full of cosmetic rewards. The patch features new Transmogrification Items, new Pets, and finally some Extra Rewards. As of now, there are not much information shared about the upcoming content of the patch. What we know for sure is there will be a new type of Treasure Goblin that will reward players with new pets.
If you are interested in the more detailed overview of the patch here is the link to the official announcement.