You may choose an Eldrazi card you own from outside the game or in exile, reveal that card, and put it into your hand.
7/13/2016 In a casual game, a card you choose from outside the game comes from your personal collection. In a tournament event, a card you choose from outside the game must come from your sideboard.
7/13/2016 A card that is exiled face down has no characteristics. You can’t choose it, even if you’re allowed to look at it.
7/13/2016 An Eldrazi card is one with the subtype Eldrazi. Noncreature cards with devoid from the Battle for Zendikar block are Eldrazi-themed, but they are not Eldrazi cards.