The two that immediately come to mind are swirls and crimped cards, two diametrically opposed aesthetics that have emerged as huge marketing tools for sellers over the last year or so
Unlike many card games where you can splash any color, here your choice defines how you win: fast aggression, clever control, massive resource swings, or dramatic comebacks
You could also probably argue that Strip Mine or even Blood Moon are even more broken because they can stop Mishra's Workshop, either by blowing it up or turning it into a Mountain
There are only a handful of good combo decks left in the format after the Simian Spirit Guide ban, which is where a free Negate is usually at its strongest
If youre in a combo-heavy deck, you can set things up so that, whichever pile your opponent picks, youre putting your win into play
Kitesail Freebooter This new addition has not had too much testing yet but early indications suggest it is a big winner