Lurker says "in the supply" that inlcude technically only the top card of each pile at the moment you play them.
From the wiki on "supply"
From the wiki on "supply"
QuoteOrdinarily each pile in the Supply consists of several copies of the same card. The four exceptions to this are Ruins, KnightsKnights.jpg, CastlesCastles.jpg, and Split pile cards, which are each Supply piles containing more than one differently named cards; in these cases, only the top card of the pile is visible to players and available to be bought or gained. For this reason, although the entirety of any Supply pile is physically part of the Supply, only the top card of any pile is considered to be "in the Supply". For instance, when Band of MisfitsBand of Misfits.jpg requires you to choose a "card in the Supply", you may not choose a card in the Ruins or Knights pile other than the one on top.