Eloise, Nephalia Sleuth is a mythic Legendary Creature — Human Rogue card from Midnight Hunt Commander (MIC), collector number 3. Current market price: $0.36 (foil $0.37), TCGplayer market prices via Scryfall.
Whenever another creature you control dies, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.") Whenever you sacrifice a token, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)