Rielle, the Everwise is a mythic Legendary Creature — Human Wizard card from Ikoria: Lair of Behemoths (IKO), collector number 342. Current market price: $5.99 (foil $15.68), TCGplayer market prices via Scryfall.
Rielle gets +1/+0 for each instant and sorcery card in your graveyard. Whenever you discard one or more cards for the first time each turn, draw that many cards.