5) Echo I think this mechanic still has some room to play around with
Its been crushing it in Standard, and in Modern for that matter, ever since Cori-Steel Cutter dropped in Tarkir: Dragonstorm
Every upkeep, you get a free impulsive draw (exiling cards off the top of your library and being able to play them that turn), but then, for each land card you exile, you get a 3/1 dinosaur token, and for each nonland card you exile, you get a Treasure token
This means within one turn cycle, you will be able to untap with six 2/2 Zombie tokens that get both +1/+1 and menace
He also has a Blood Artist effect: whenever another creature dies, you gain one life and target opponent loses one life
Green decks can take this further, and there are some legendary matters synergies that might lure greedy drafters towards a four- or five-color build, but this is nowhere near as viable as in, say, Tarkir: Dragonstorm