Coax from the Blind Eternities
Oracle Text
You may choose an Eldrazi card you own from outside the game or in exile, reveal that card, and put it into your hand.
Card Rulings
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.
Every. Damn. Time.
In a tournament game, "from outside the game" is limited to your sideboard.
Come on, let me find it with ancient stirrings.