Cartographer's Companion is a common Artifact Creature — Gnome card from The Lost Caverns of Ixalan (LCI), collector number 248. Current market price: $0.14 (foil $0.10), TCGplayer market prices via Scryfall.
When this creature enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")