33 cards where the illustration contains “vendor”

Armistice (Mercadian Masques #3)
Balloon Peddler (Mercadian Masques #59)
Bane Alley Broker (Gatecrash #145)
Bazaar Trader (Worldwake #72)
Cornered Market (Mercadian Masques #14)
Corpse Traders (Avacyn Restored #90)
Customs Depot (Mercadian Masques #71)
Dark Bargain (Dominaria #83)
Discerning Financier (Wilds of Eldraine #10)
Discerning Peddler (Outlaws of Thunder Junction #121)
Edgewall Innkeeper (Throne of Eldraine #151)
Embargo (Mercadian Masques #77)
Festival of Trokin (Portal Second Age #16)
Gem Bazaar (Astral Cards #12)
Gwafa Hazid, Profiteer (Conflux #110)
Ivy Lane Denizen (Gatecrash #125)
Market Festival (Journey into Nyx #130)
Market Gnome (The Lost Caverns of Ixalan #22)
Merchant of the Vale // Haggle (Throne of Eldraine #131)
Merchant of the Vale // Haggle (Throne of Eldraine #293)
Merfolk Traders (Weatherlight #43)
Nightshade Peddler (Avacyn Restored #187)
Provisions Merchant (Wilds of Eldraine #321)
Renari, Merchant of Marvels (Commander Legends: Battle for Baldur's Gate #90)
Seller of Songbirds (Return to Ravnica #22)
Spawnbroker (Ravnica: City of Guilds #65)
Spellbook Vendor (Wilds of Eldraine #31)
Stadium Vendors (Battlebond #63)
Thieving Magpie (Seventh Edition #104)
Trading Post (Magic 2013 #220)
Trusty Packbeast (Core Set 2019 #41)
Urban Utopia (Guilds of Ravnica #146)
Verdant Haven (Gatecrash #138)

The message was clear to Sorin—time to search for something else.