A standard is a thing against which other things are measured, or by which they are defined.Huck wrote: How you define "standard"? How you define "rules"?
A secondary meaning is that it is the most common object in its class - for instance, when we might say in English "a standard pack of playing cards", we mean the 52-card "English"-suited (really French) pack, with four suits - Hearts, Diamonds, Clubs, Spades, and three face cards, Jack, Queen and King. But this pack is SO "standard" that we don't even say "standard", we just say "a pack/deck of cards." Many people don't even know there is anything else.
For people to have known what carte da trionfi were, used to play the game of triumphs (or just "triumph"), there had to be a standard object to which they were referring.
This explains why Marcello called Michelino's cards a "new kind of triumph cards" - it wasn't the iconographical content he was comparing it to/measuring it against, so it had to be the structure. The gods and heroes were obviously distinct from the suits, just like the trionfi were distinguished from the suits in a pack of standard carte da trionfi.
We have even a complete Tarocchi deck from 15th century, the Sola Busca. We have complete descriptions of two others, the Boiardo Tarocchi poem and the Michelino deck. We have complete Mantegna Tarocchi in great number, also some, which are complete.
You ignore, that complete German decks from the time have survived.
The E/S Series are not cards, and not a game.
Sola Busca and Boiardo both have 22 trumps, which shows they too are based on the standard triumphs. Both are free re-creations of the standard series, just like many modern Tarots are.
The German and Flemish packs are also based on the regular model of playing cards - pips and courts in a suit. It doesn't matter that they are unique or beautiful, they are still based on a model and a number that everyone understood. They weren't just wild inventions doing anything they wanted. Ultimately, they are playable for normal card games.