Debtors' Knell is a rare Enchantment card from Guildpact (GPT), collector number 141. Current market price: $1.04 (foil $20.00), TCGplayer market prices via Scryfall.
({W/B} can be paid with either {W} or {B}.) At the beginning of your upkeep, put target creature card from a graveyard onto the battlefield under your control.