Un'goro Crater Guardian Stone Farming Location (Classic - WoTLK)
One of the most under rated farming locations in the entire game is the Stone Guardians in Un'goro Crater. These mobs drop the Guardian Stone item along with Essence of Earth, both of which you can sell on the Auction House. Depending on how many people are farming the Guardian Stones on your server determines how much gold per hour you'll make farming here.
Classes that are capable of kiting - even a little - will easily be able to defeat these Stone Guardian enemies. They've very slow moving and they're also susceptible to basically every form of movement impairment and root debuff in the game. I even see restro druids taking them out by spamming Wrath/Moonfire and root rotting them with Entangling Roots.
The Stone Guardian enemies that you need to farm don't have a static spawn point and if you aren't looking in the right places - you won't find any. If you're unfamiliar with their pathing and where to look for them I recommend using my screen shot below for some extra guidance.
Since this is Un'goro Crater there are a ton of extra goodies you can find while hunting here. Herbalists, Miners and Skinners will all benefit from this location. Unlike the Herbalists and Miners, Skinners will have to go out of their way a little bit to make extra money here. Any time you see a Devilsaur you'll want to take it out so you can skin it, the Devilsaur Leather is worth a couple gold each since it's used to make some of the best pre-raid DPS gear for multiple classes. For more information about the Devilsaur Leather Farming, follow the link provided to be taken to that guide.
To make things easier, I have created two short lists below that go over each of the Mines/Herbs you should expect to find in Un'goro Crater. Don't forget to stop for the piles of dirt you see throughout the zone too, they yield Un'goro Soil which you can sell on the Auction House too. If you know that Power Crystals sell too then you can stop for those that you see too, but I wouldn't recommend it.
Un'goro Crater Herbs: Mountain Silversage, Blindweed, Sungrass, Dreamfoil, Golden Sansam
Un'goro Crater Mines: Rich Thorium, Small Thorium, Mithril Deposit, Truesilver Deposit
For more information about the best routes for gathering profession in Un'goro Crater check out my Un'goro Crater Mining Farming Guide and Un'goro Crater Herbalism Farming Guide. Both of them have tons of information about gathering that this guide does not.