Harvest Mage is a common Creature — Human Spellshaper card from Nemesis (NEM), collector number 105. Current market price: $0.09 (foil $1.06), TCGplayer market prices via Scryfall.
{G}, {T}, Discard a card: Until end of turn, if you tap a land for mana, it produces one mana of a color of your choice instead of any other type and amount.