So what cards do the bottom 3 mats come from?
I do not understand your question. All six on the right are mats for Victory tokens. None of them is card-specific. About the cards on the left, i have no clue. The Trade Route mat in germany shows the Trade Route art, a giant coin symbol and a descriptive text how the mat is used.
By the way, there are 8 VP mats in the german version of Prosperity, too. I guess the reason why there are eight is that this way, you can play with whatever mat you find the most appealing. Personally, i like to "be" the alchemist
Edit: Ah, i guess you are talking about those on the left. Pretty sure they are box art. The tree thing is from Prosperity, and the left one
might be is from base.