Mycosynth Wellspring is a common Artifact card from Duel Decks: Elves vs. Inventors (DDU), collector number 56. Current market price: $0.39, TCGplayer market prices via Scryfall.
When this artifact enters or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.