Insidious Roots is a uncommon Enchantment card from Murders at Karlov Manor (MKM), collector number 313. Current market price: $1.72 (foil $3.13), TCGplayer market prices via Scryfall.
Creature tokens you control have "{T}: Add one mana of any color." Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.