All cards are identified by rarity. There are five "core" rarities in ascending order: common, uncommon, rare, very rare, and extremely rare. There are also two “special” rarities: chase and variant. Chase cards are typically unique in some way, either holding special significance to the artist or displaying a different style from core cards. Variant cards are modified variations of core cards in the same series. Variants have been retired for new releases and will only be found in series published prior to 2017.
Each series detail page includes the number of copies of each rarity, the name of each card, and your progress toward collecting all the cards in the series.
You can also get a quick overview of the rarities for each series by clicking on the series progress meter.