Goddess of Tarot
Fortuna would seem to be the most obvious choice for a Goddess of Tarot.
But I admit I am partial to Diana, with her lunar associations, and her "governance of the mysteries of the night".
I can also see how some might wish to call upon Isis, with her roots in that most ancient of (known) civilizations. [There were other cultures prior to 3000 BCE that we know very little about, unfortunately.]
Could the spirit of Tarot take a more tangible form in a new goddess, or an old one we have yet to recognize; perhaps as "Tarona" ?
I have to confess to invoking "Holy Sophia" before every reading, for guidance, illumination, protection, etc.