I just came up with a board that I like to call "so many". It basically tries to get as many different cards on the board as possible.
Tournament, Young Witch (bane: Hermit), Urchin, Grand Market, Bandit Camp, Cultist, Black Market (random), Knights, Alchemist, Fairgrounds
Plus Colony/Platinum AND Shelters. With the ten kingdom cards, plus one for the bane and nine for the extra knights, the seven base cards, plus Platinum/Colony and Potions, the three shelters, the five prizes, the four ruins, spoils, the two non-supply actions, and the fifteen Black Market cards, that comes out to... 60 unique cards. You'd never be able to get them all (unless you're Celestial Chameleon) but imagine playing a Fairgrounds on that.
Edit: Whoops! I forgot that you're only allowed to use Colony/Platinum if you have Prosperity cards in the kingdom. Goodbye Marauder, hello Grand Market.