It's not a very large theme but adds a little bit of flavor
however, this is generally inadvisable because the marginal utility of being one card harder to deck is worth less than the decrease in probability of drawing your 60 best cards that comes with each card added above 60
If it doesn't, but it's a creature card, you may put it onto the battlefield
Well, while I am not at liberty to tell you which cards were made to play nicely with Khans of Tarkir block, I can say that it is normal practice for us to make sure that a handful of cards in each core set play nicely not just with the current environment, but the future environment as well
This helps you put cards like Reversal Energy to work and, due to the wording, would also be able to fetch Ace Spec cards that are treated as Special Energy
For this, the budget will change depending on what Bracket I am looking at, but I kept it tight