The Eye of Anubis Hologram is a foil symbol placed at the bottom right of all official Yu-Gi-Oh! cards, with the exception of some very early prints in the OCG such as those in Starter Box. Contrary to its appearance, it is not a sticker, but is printed directly onto the card.
The hologram serves as counterfeit protection as well as being used to identify the edition of a card. All Limited Edition and 1st Edition cards, in addition to being labeled as such on the card itself, will have a gold Eye of Anubis Hologram, while Unlimited Edition cards will have a silver one.
Stars were added to the hologram with the release of Shadows in Valhalla in 2018. All cards printed after this date have stars in the hologram.
Official Proxy images of cards lack this hologram, either missing it entirely or replacing it with a solid square.