These only exist as mentions in other cards' texts and use the artwork of one of those cards in video game appearances.
Has artwork
These have been given unique artworks in video game appearances.
Specific print
These have a physical release with an artwork that makes them recognizable as a specific Token, but none of the properties (including name) of that Token.
Named print
These have been released as physical cards with a specific name and properties.
Generic
These are not representative of any specific Monster Token and do not have any properties (such as ATK or Type). They sometimes have custom flavor text and artwork.
Tokens/Counters
These have a custom name and are stated to also represent any counter, in addition to Tokens.