Showdown of the Skalds is a rare Enchantment — Saga card from Kaldheim Promos (PKHM), collector number 229p. Current market price: $0.85 (foil $1.20), TCGplayer market prices via Scryfall.
(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Exile the top four cards of your library. Until the end of your next turn, you may play those cards. II, III — Whenever you cast a spell this turn, put a +1/+1 counter on target creature you control.