I’ve never given any thought to who might have designed and/or illustrated Tarot Cards, I suppose because I figured they were something that evolved over time and were already established by the time card/game companies began printing them. The popular version that I am familiar with turns out to have been illustrated by one Pamela Colman Smith, an illustrator who attended (but did not finish) Pratt and who seems to be fairly well forgotten at this point.
Pamela Colman Smith (16 February 1878 – 18 September 1951), also nicknamed Pixie, was an artist, illustrator, and writer. She is best known for designing the Waite-Smith deck of divinatory tarot cards (also called the Rider-Waite or the Rider-Waite-Smith deck) for Arthur Edward Waite.
The Beinecke Rare Book & Manuscript Library of the Yale University Library: http://brbl-dl.library.yale.edu/vufind/Author?author=Smith%2C+Pamela+Colman&type=Author
Special Collections Department, Bryn Mawr College Library: http://www.brynmawr.edu/library/speccoll/guides/smith.shtml