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 is extremely limited and 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 indicates the card is a variation of a core card in the same series. The underlying artwork is the same, but the artist has presented the image in a different way from the original core series card. In the example below, you can see "Cooz" and its variant "Cooz [Sketch]".
Variants are created at the discretion of the artist and are not found in every series.