Esper Sentinel taxes opponents noncreature spells unless they let you draw a card, which fits perfectly in Modern's Hammer Time decks. As a one-mana artifact creature, it synergises with metalcraft, equipment and Urza's Saga tutoring. Its ability to generate card advantage while pressuring life totals makes it one of the best white one-drops in the format. These synergies cement its role as a key card in modern artifact-aggro strategies.