Four of the Market Cards are actually Basic so they don't go into the Market deck.
Are these just there to cater for the Ranger characters?
Oh, those four.
The four cards that the Chaos in the Trollclaws tells you about in the Adventure instructions
Alternate Card Art
Additional Basic cards with alternate art will be included in various releases. For example, the Glory in Chaos in the Trollclaws. Except for the alternate art, these cards are identical to the versions from the base game