Nissa's Encouragement is a rare Sorcery card from Hour of Devastation (HOU), collector number 203. Current market price: $0.15, TCGplayer market prices via Scryfall.
Search your library and graveyard for a card named Forest, a card named Brambleweft Behemoth, and a card named Nissa, Genesis Mage. Reveal those cards, put them into your hand, then shuffle.