You can see from the video that the categories are Featured, Pets, Mounts and Consumables. Each contains just what you'd expect, the items off the battle.net store. And there's also several neat features in there, including little marks to indicate pets that you already own, and a pop-out to zoom in on the animated pets and mounts.
The consumables category is fairly empty right now, just showing off the +XP elixirs in sets of one and five. What they don't seem to have any more is the Lesser Charms, maybe the reaction to those coming to an in-game store was too strong. This achieves Blizzard's goal of making the store accessible without leaving the game. However, the previous Adriacraft post talked about other, hidden categories in the files, like armor and weapons. Let's see whether they appear.