Worldwalker Helm is a mythic Artifact card from The Big Score (BIG), collector number 37. Current market price: $14.72 (foil $22.81), TCGplayer market prices via Scryfall.
If you would create one or more artifact tokens, instead create those tokens plus an additional Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.") {1}{U}, {T}: Create a token that's a copy of target artifact token you control.