The augmented reality (AR) stickers from Google are a fun trick of the camera application on your Pixel smartphones. You can place animated, sometimes promotional characters such as Star Wars stormtroopers or the Stranger Things team, in the frame that captures your camera and look almost convincingly real.
Google has also released additional packages of AR stickers that include some "foodmoji" characters (a hamburger, donut, coffee cup, etc.) and the ability to have 3D text floating in the AR space. But now the company has removed those two packages from the main AR Stickers application and given them separate Play Store listings, allowing Pixel owners to save a little space on their phones if they have no interest.
And I want to say a little. As pointed out by Android Police, the foodmoji package is 24.66MB and the text package comes to just under 5MB, so it is not saving all that storage, but it's something. Remember that Google's ARCore technology does most of the work here and the main AR Stickers software is still required. You can not simply download these add-ons and use them independently. That means that these AR adhesive labels are still very much pixel-only. But ARCore is gradually extending to more and more Android phones to enhance and optimize the augmented reality experience for the entire platform.