The 12-Post and Tron decks that Kozilek, the Great Distortion slots into naturally have a pretty good converted mana cost spread for its discard to counter ability
Both of them have shot up this year, but you can still find people who will trade the Prerelease version Emrakul for less than the $20 it books for
In a one-on-one game, this card is practically a death sentence for the other player, taking out their whole board and stocking your hand full to bursting with new options even if you dont finish them off on the same turn
First up is a fan-favorite Planeswalker reprint: Ugin, the Spirit Dragon
The catch is that four-color decks are inherently less consistent than two- or three-color ones, and the decks spell-heavy plan needs a critical mass of cheap interaction to really come online
So that's a few thousand more, so the Commander community disagrees with me by a bit but I'm sure you can see why I went in this order