Sigarda, Champion of Light is an excellent human lord that can give you more humans when it attacks, while Sigarda, Heron's Grace gives your humans hexproof
Of course, there are ways to guarantee you will always guess it correctly
You can cast Black Sun's Twilight without a target (presumably with X equal to 5 or more) just to return a creature card
Land Tax, known as the white Ancestral, allows a player who's behind on the land count to search his or her library for three basic lands a turn, and then draw the normal card for the turn on top of the previous trio
First, we learned that all five of the classic clans from Khans of Tarkir are returning in this set - Abzan, Jeskai, Mardu, Sultai, and Temur are all present and correct
However, those are so legendary that they tend to be sold graded or via specialized auction houses, not on the open, secondary card market