Winter's Rest is a common Snow Enchantment — Aura card from Modern Horizons (MH1), collector number 78. Current market price: $0.29 (foil $0.57), TCGplayer market prices via Scryfall.
Enchant creature When this Aura enters, tap enchanted creature. As long as you control another snow permanent, enchanted creature doesn't untap during its controller's untap step.