Confront the Unknown is a common Instant card from Shadows over Innistrad (SOI), collector number 198. Current market price: $0.09 (foil $0.48), TCGplayer market prices via Scryfall.
Investigate, then target creature gets +1/+1 until end of turn for each Clue you control. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")