Another good place to farm Transmog in World of Warcraft is Desolace. West of the Cenarion Wilderness is a small canyon full of Nagas waiting to be looted. This is best done with a Druid or a Tank Monk (statue) so you can reach many Nagas. The advantage of this spot is that the Nagas spawn again very quickly and you can get many kills per hour.
Zone: Desolace (Kalimdor)
Farming Route
So all you have to do to get some rare items is just stand on a spot (as a druid), spam Moonfire or Sun Fire and after about 2 minutes fly from spot to spot and loot. As a monk, just place a statue and eat the speed buff food Bear Tartar beforehand to run faster.
What items can be found in this zone?
Short explanation: Since the prices for Transmog fluctuate strongly depending on the server, I no longer give fixed values in gold. The more valuable items are simple marked with more stars. An item with 5 stars 
is worth more than an item with only one star in comparison. I hope this gives you a small impression on which items to be excited about when farming!