Explorer's Cache is a uncommon Artifact card from The Lost Caverns of Ixalan (LCI), collector number 184. Current market price: $0.21 (foil $0.27), TCGplayer market prices via Scryfall.
This artifact enters with two +1/+1 counters on it. Whenever a creature you control with a +1/+1 counter on it dies, put a +1/+1 counter on this artifact. {T}: Move a +1/+1 counter from this artifact onto target creature. Activate only as a sorcery.