7 Wonders Duel: Sagrada Familia is a promo card for 7 Wonders Duel distributed through the Geek Store on BGG.
It allows you to randomly draw 3 Progress tokens from among those discarded at the beginning of the game. Choose one, play it, and return the other 2 to the box. This Wonder is worth 4 victory points.
The Sagrada Familia card is just an alternative art (and name) of The great library card included in the base game. The price and the effect of the two cards are identical.