Vendor Mods
AlreadyKnown
Colorizes items that you already know in default merchant and auction frames.
WoWInterface
GnomishVendorShrinker
GnomishVendorShrinker creates a simple, compact vendor frame. GVS brings an interface similar to Auctioneer's "CompactUI" to the vendor frame.
WoWInterface, Curse, github
GoblinVendorFilter
GoblinVendorFilter adds a small button to the merchant window. This button enables you filter the current merchant window items by itemType, subType and equipLocation. The filter clears each time you close the merchant window the filter resets to ensure that you do not miss out on great deals next time you visit a merchant.
Curse
Peddler
Allows you to flag items that you plan to sell, automatically selling them later when you interact with a vendor. It automatically flags gray items you loot to be sold, but you're free to un-flag them.
Curse, WoWInterface
Reagent Restocker
Reagent Restocker is a simple addon for automatically purchasing items, selling unwanted items, and repairing. Unlike many other similar addons, Reagent Restocker supports drag and drop and has a full GUI for editing buy/sell lists. Even though it may be more useful to some classes than others, Reagent Restocker works for all classes.
Curse, WoWInterface
Scrap
Have you ever felt tired of selling, over and over, all that items you don't need at the merchant? There are several addons that lets you create a "junk list" and sell all the junk in your bags with a single-click, but they are always hard to use and doing the simplest tasks, like changing their filters, can be a real pain. Scrap tries to fill this hole: it is designed to be an easy to use and intuitive addon, but lightweight at the same time. If you are tired of slash commands and hard configuration, then this is the addon for you!
Curse
Sell-O-Matic2
The purpose of this mod is to help selling items in an easier way than just clicking all of them in the merchant. Uses filters and modules to set items to be sold or destroyed.
Curse, WoWInterface
StealYourCarbon
A simple reagent restocker addon. When you visit a vendor who sells an item you have told SYC to buy, it buys it for you.
WoWInterface, Curse, github
Review:
WoW Insider
tekJunkSeller
Simple addon that automatically sells all your grey items when you visit a vendor.
WoWInterface, github
VendorMaster
Auto-sell gray items at vendor, Auto-repair at vendor, Build a shopping list of reagents to keep stocked, Auto-buy items to restock your shopping list, "Save List" to ignore gray items when auto-selling, Option to print out costs and profits from the transactions.
WoWInterface
Watto
Tool for buying massive amounts of items, and selling your junk items!
Curse