This is my current Legacy tourney deck. I'm still putting the finishing touches on it, but it's served me very well so far.
If you can't tell by the name, this deck revolves around the landfall ability of Hedron Crab. Green is in here to maximize landfall and for mana acceleration, making this deck as fast as any mill deck I've ever seen.
Evolving Wilds and Terramorphic Expanse allow me to play multiple lands a turn even on the first few turns which vastly accelerates the landfall of even two Hedron Crab, as well as letting me find the basic lands I need. Kodama's Reach, Harrow, Scapeshift, and Search for Tomorrow allow the same, accelerating the deck as well. Khalni Gem plays an interesting part by allowing me to produce colors of mana I lack, while also replaying lands.
Worldly Tutor allows me to get more Hedron Crab or Dryad Arbor early game; or Lord of Extinction or Nemesis of Reason late game. Followed Footsteps plays a similar role. Noxious Revival allows me to recover lost lands (or crabs), or put a useless card that I've already milled from an opponents deck back on top of their deck, stalling them a bit. Surgical Extraction gives me more control over my opponents remaining deck.
Just about everything else is for straight-up milling.
Bojuka Bog is good to mainboard when you're facing down a zombie or other graveyard manipulation deck, but consider removing Lord of Extinction if you do, as he'll be considerably weaker then. The rest of the sideboard should be fairly self-explanatory.
The maybeboard is full of cards that I would love to put in the deck, but for the most part can't justify the mana costs (making the card too late game to make a huge difference, or like Glimpse the Unthinkable where black mana is not usually gained until later, and is therefor more situational than Memory Sluice (which can easily be conspired by tapping all the Hedron Crabs I have out)) or situational limitations (like Psychic Surgery requiring my opponent to shuffle, or Unearth requiring me to have dead Crabs/Dryads).
Suggestions are greatly appreciated, but when/if you find something to criticize then please make it constructive criticism.
