All-Seeing Arbiter is a mythic Creature — Avatar card from Streets of New Capenna (SNC), collector number 286. Current market price: $0.54 (foil $0.64), TCGplayer market prices via Scryfall.
Flying Whenever this creature enters or attacks, draw two cards, then discard a card. Whenever you discard a card, target creature an opponent controls gets -X/-0 until your next turn, where X is the number of different mana values among cards in your graveyard.