Village Rites is an all-star for Aristocrat synergies, and Tooth and Nail can tutor up a whole series of game-ending combos for its Entwine cost
A 5/5 for one mana of each color, Sliver Hivelord gives you an indestructible army of Slivers
If you pick up a couple of UR/UB duals and a World Map, you could use those to splash the powerful Shantotto, Tactician Magician, which plays incredibly well with those spells
Some of the strongest cards the game has seen since launch have made their way into the card pool, bringing unexpected combinations and new features to colors that haven't seen them before
Not background necessarily, but some other line of text that says something along the lines of Whenever you sacrifice a Treasure token, give a creature a +1/+1 counter and trample until end of turn. That would make it a lot more interesting and powerful, but I suppose not every card needs to be great