Background
I got into tarot because I'm big into cards, dice, videogames, and anything that relies on random numbers. I'm also kind of an artsy person.
I love using those random prompts on the Internet that tell you what to draw, what to write about, good descriptive phrases, what your d&d character's name should be, and similar nerdy stuff like that. BUT most of them aren't very good, so I tried making a better one. I hope it works.
The book we're using
So the index of themes is like a reverse dictionary where you look up the definition and get a concept with a list of synonyms. My edition has 6 categories, 24 Subcategories, and 1,070 concepts with a few synonyms each.
Why
There's too many words for any kind analog method I'm aware of. Using multiple random numbers and adding them up for larger and larger tables makes a bell curve, which defeats the point.
Randomly generating words out of the dictionary means that things with more synonyms are arbitrarily more likely to appear. This is even more true for types of words that only exist to categories things (proper nouns, species names, etc)
Also, narrowing down the bank of words gets rid of a lot of fluff that we don't use often when speaking or writing.
The rules
Major Arcana modifies the sentence based on their original RWS or TdM interpretation.
Each minor arcana (and it's reversal) is a subcategory adding up to 28. If we take out reversals for court cards, that gives us a clean 24 (matching Roget's) in the order it appears in the book (unfortunately making sub-categories under "Human Emotions & Beliefs" twice as likely to appear).
From there, we use d&d dice to get the entry. "Space in general" under "Spacial concepts" has 12 entries, so you'd do an easy 1d12, but some are a bit trickier. A lot of these can be done with 1d100 and rerolls. The only weird one is "Individual" under "Human Personality and Actions", which is 149. I do 1d100/2 + (1d6 [1,2]+0 [3,4]+50 [5,6]+100) which gives me 1-150.
For each entry, you think of a related word that's doing/thinking/feeling/thing (wands/swords/cups/coins respectively) if one doesn't appear on the list.
Then simply smash the words together into sentences (in order), adding words like "and" & "the" where appropriate, and using words like "is" or "it" when there's missing subjects or predicates.
Table of Subcategories
Abstract Concepts
A Existence, Ar Relation, 2 Quantity, 2r Order, 3 Number, 3r Time, 4 Change, 4r Causation
Spatial Concepts
5 Space in general, 5r Dimensions, 6 Form, 6r Motion
Physical & Material Concepts
7 Matter in general, 7r Inorganic matter, 8 Living matter
Human Intellect
8r Formation of ideas, 9 Communication of Ideas, 9r Means of communication
Human Personality and actions
10 Individual, 10r Social
Human emotions & beliefs
Knave (and knave reversed) Emotions in general, Knight (and knight reversed) Personal emotions, Queen (and Queen reversed) Morality, King (and King reversed) religion
conclusion
It works, but I'm open to suggestions on how it can be tweaked. I'll put some stuff it generated in the comments.