I think my overall favorite has to be Blightsteel Colossus, though the original art is iconic, but very static
While this wont grab land cards from your deck, if you combine it with some incidental card draw thanks to other colors, you can quickly end up with an unmatched number of Lands on board
Which makes sense when you look at its other printings: the cheapest version from Baldur's Gate is worth close to $100, for a card that is one of Magic's best dragons, an amazing treasure card, and a cEDH staple
If I can loop a card into the graveyard again and again, even if I'm not making extra mana or creating anything in the process, I'll get that many 1/1 Black Fungus tokens on my end step
Vampiric Bloodlust A fascinating little set was creeping around the corner: Ixalan would come out two months after Commander 2017 and bring 11 white Vampires, and Rivals of Ixalan would bring 10 more unique white Vampires
Can You Print MTG Cards With Custom Mana Symbols and Frames