So...what do the Harrow Cards look like "in game"?
Do they have a specific pattern on the back? What is the pattern generally called/known as?
What are the cards made of? I presume they are hand drawn and painted.
Are there famous/infamous decks or designs?
CJ
I'd say that this goes in two directons:
The traditional harrow decks used by varisian harrowers are probably elaborate pieces of art, with dignified pictures and very fancy, hand-painted back covers. I'd say that no two of these decks are quite alike, being made by traditional artists.
And then there's the deck gamblers use for Towers. They're cheap, mass-produced affairs. The back covers are nothing special, the designs themselves not very dignified. They reflect the base desires of the gamblers using them.
A variation to the Towers decks, more elaborate, but still not traditional decks will be around, expensive affairs for noble players and politicians from Absalom (who use Harrow analogies in their plots ans scheming).
Of course, you'll sometimes see traditional decks being used by gamblers - these decks are looted from Varisians who fell victim to bandits or worse.
On the other hand, some anti-traditionalists among the Varisians - some who want to be more modern, but without selling out all their values - might use less traditional decks. Maybe not the most seedy ones (with naked ladies painted on both sides. You haven't seen nothing if you haven't seen THAT paladin. Not to mention the way they protray the beating...), and some will try to get a nobles' decks.