Scrap (Junk Seller)
Scrap sells all your junk when you visit a merchant, but not just grays.
It comes with multiple (optional) intelligent junk filters, and can even memorize which items you normally sell. More importantly, it is designed to be very easy to configure which items to sell and tags junk items in the inventory accordingly. It can also automatically repair your equipment. Finally, a wide assortment of plugins are available that add extra functionality, such as support for Bagnon, ElvUI and DataBroker, or an automatic inventory cleaner.
Now you inventory can breathe.