On NeonMob, there are five "core" card rarities: common, uncommon, rare, very rare, and extremely rare. There also exist two types of "special" rarities: chase and variant.
A chase is a special type of rarity. It may be extremely limited or somehow different from the main cards in the series. It is represented by this rarity symbol:
A variant is a special type of rarity that typically indicates the card is a variation of a core card in the same series. In the example below, you can see "Cooz" and its variant "Cooz [Sketch]".
Variants have been retired for new releases and will only be found in series published prior to 2017.