Here is a list of mobs/areas which you can farm for gold extremely efficiently!

You can farm the stockades in Stormwind City for easy greens and wool + linen cloth. This is THE BEST dungeon/instance to farm wool cloth because every other kill yields 3-5 pieces of wool and there are about 100 npcs in this instance. A stack of wool can go from 77silver to 2 World Of Warcraft Gold on the AH. You can do the math.

You can farm scarlet monastary chests and locked chests for the chance to get large knapsacks (sells for 1.25-2 world of warcraft gold) or a BLUE item. I roughly get a blue item once every 11th locked chests. If you focus on the graveyard, library, and armory (NOT CATHEDRAL), then you can easily get about 8 locked chests an hour, and about 10 regular chests. Need a rogue to lockpick or take blacksmithing and use Golden Skeleton Keys (requires 150 blacksmith skill).

You can farm furlbogs in southern map of Felwood for 1-3 pieces of mageweave every 3.5th kill. About 40 npcs in the area. Easily can make 100 mageweave an hour and 9 World of warcraft gold an hour off coin drops, for a total of 20-27 World Of Warcraft gold an hour.

You can farm Zul'Farrak outside in Tanaris zone for 2-5 pieces of mageweave every 3rd kill. About 40 npcs spread around that region. Can easily make 5 World Of Warcraft Gold an hour off coin drops and 80 mageweave an hour and sell that on the auction house for 10 World Of Warcraft Gold.

You can farm western plaguelands at the felstone field and field next to it for easy 25 world of warcraft gold an hour, traveller backpacks that sell from 15-27 world of warcraft gold an hour, and 1-3 pieces of runecloth every 5th kill. You can easily make a total of 60-120 gold an hour if you grind fast and it is not camped (which usually it isn't). Both farmsteads have about 60 npcs or 80npcs. Plenty for everyone.

Farm the center of thelsamar. There is an island full of troggs that are level 13-15 called stone splinters that drop 1-3 cloth every 3rd kill. Drops a green every 10th kill.

Farm the south of thelsamar to kill level 9-11 troggs that drop 1-3 cloth every 5th kill. Drops a green every 10th kill.

Can farm Whelplings on the east side of badlands in lelthor ravine. They drop "Dark Whelpling" which can sell for 35-200gold on the auction house. They make great companions and gold generation.

You can farm ShadowFangKeep south of The Supulcher south of the Undercity. They also drop the Horde equivalent of 3-5 wool cloth per kill and 3-5 linen cloth. There are about 300 npcs here. You can make about 5 World Of Warcraft Gold an hour off coin drops and another 20 World Of Warcraft Gold off greens and Wool Cloth sales on AH.

Can grind ragefire caverns in Orgrimmar (horde only or suicidal alliance) for 3-5 linen cloth 80% of the time off humanoids, and massive amounts of low level greens. Some greens sell on the ah for 1-2 World Of Warcraft Gold each to twinks. A green drops roughly every 7th kill.

You can farm normal rock elementals in the south, middle edge of The Badlands zone (nestled in a small valley). They drop a lot of grey loot that vendors for 50silver to 1.5 World Of Warcraft Gold and drop it every other kill. They also drop ELEMENTAL EARTH which sells on the ah for 1-3 World Of Warcraft Gold A PIECE. Average drop of the earths is 1 out of 17.

Can farm greater obsidian elementals in the middle of Searing Gorge zone. They drop an elemental earth every 20th kill and an essence of earth every 33rd kill. You can easily get 3 essences and 5 elemental earth's an hour, and resell them for a whopping 70 world of warcraft gold or more.

Can kill level 53-54 toxic horrors in felwood on the middle top area of the map, west of the alliance flight path for essence of waters every 18th kill. These essences of water sell for 7-20 world of warcraft gold each.

Can kill level 55-58 undead in eastern plaguelands for essence of water that drop every 33rd kill. While this isn't a good ratio, there are hundreds of these. Concentrate on the middle of the map where you can find Plague Monstrosity, Plague Ravager, Blighted Surge, Discordant Surge, and Blighted Horrors. These essences of water sell for 7-20 world of warcraft gold each.

Can farm Living blaze level 54-55 for Essence of fire every 50th kill in Un'Goro crater. Level 53-54 Scorching Elementals in Un'Goro crater for Essence of fire every 20th kill. Sell the essence of fire for 7-20 world of warcraft gold on the auction house, each.

Can kill entropic Beasts in the middle part of felwood for essence of fire every 100th kill. Not great but if you want an uncamped spot... Sell the essence of fire for 7-20 world of warcraft gold on the auction house, each.

Can kill Dust Stormers in Silithus for essence of airs on the entire top side of the map that drop every 70th kill. Can kill Whirling Invaders that spawn from the event for essence of airs that drop every 20th kill. Can kill level 58 Cyclone Warriors for essence of airs that drop every 30th kill in the middle to bottom part of silithus. Sell these essence of airs for 15-30 world of warcraft gold each due to higher rarity.

You can farm elemental slaves on the west side of Alterac mountains (horde only) for the chance to get elemental earths (1 out of 15 kills). Goes for 1-3 World Of Warcraft Gold a piece on Auction House.

Can farm elemental exiles on the southwest area of Arathi Highlands for elemental earths. Same 1-3 World Of Warcraft Gold per earth on AH.

Can farm Dabryie's farm in Arathi Highlands (horde only) for 30 npcs of 2-6 silver each on 3-5 minute spawn timers. Often times not camped. Easily can generate 1-5 World Of Warcraft Gold an hour, more if you are an AOE class.

Can farm Go'Shek farm in Arathi Highlands (alliance only) for 30-40 npcs of 2-6 silver each on 3-5 minute spawn timers. Often times not camped. Easily can generate 1-5 World Of Warcraft Gold an hour, more if you are an AOE class.

You can area of effect the scarlet monastery graveyard (in Tristfall glades northeast corner of map) for a good 2silver - 6 silver per kill. An aoe class can easily farm and reset the instance for a good 30-60 World Of Warcraft Gold an hour.

You can farm warpwoods and deadwoods (funny, walking tree treant guys) for 2-10 silver, rare herb drops that sell for 1-5 World Of Warcraft Gold EACH, major healing potions (sells for 1-1.5 World Of Warcraft Gold each on my server), and Living Essences (sells for 8-14 World Of Warcraft Gold EACH on AH!). The warpwoods are located on the north side of Felwood zone near the alliance flight path person. The deadwoods are located just southwest of where the warpwoods are. I made an easy 40-80 World Of Warcraft Gold an hour depending on AH prices with my 60 PALADIN. If you have any other faster dps class, you can EASILY get DOUBLE the World Of Warcraft Gold per hour I got (I should've rolled a different class.... *cries*).

You can farm twilight hammer elites in Searing Gorge. They are located JUST WEST of the alliance/horde flightpoints. You can easily get 3-5 mageweave cloth per drop and about 2silver-16 silver per kill, with 9/10 silver being the most common drop of coin. Easily can make 10 World Of Warcraft Gold per hour off coin drops and 5-20 World Of Warcraft Gold per hour off the green and mageweave drops.

You can farm The Stockades elites located in Stormwind City for decent low level silvers and 3-5 wool cloth per drop on kill. A stack of 20 wool sells for 1-1.15 World Of Warcraft Gold on my server.

You can farm Dustwallow Marsh dragonkin elites (forgot name) on the south side of the map. They are actually Onyxia's guards but they are low level 41-43 gold elites. They drop a nice 3silver - 12silver on kill and can be skinned for medium and heavy leather(not sure on heavy but it might happen i think, i know medium is confirmed). They also drop the occasional 3-5 mageweave cloth. Easily can earn at least 30 World Of Warcraft Gold an hour.

You can farm Alterac Mountain ruins Ogre elites for easy, quick cash (located in middle of the map). THey are level 37-40. They drop a moderate amount of greens and once every 110th kill a blue item will drop, potions every 15th kill, and about 3-10 silver each kill. Don't forget to go inside the unbroken buildings because a named Ogre Elite resides in each one. Watch out for mel'gore the miser wandering patrol. I easily earned 40 World Of Warcraft Gold an hour.

Then there is the ultimate, the Wetlands zone. On the east side of the map leading to and near Grim Batol are level 58-60 dragonkin elites. Some of these guys drop up to FORTY-FIVE (45!!!) silver on kill! My paladin dps sucks too much to make this worth while but any dps class will love this place. It's also virtually uncamped. Just watch out for the named elite dragons that roam but they are *very* easy to avoid since they're so big, walk so slow, and you can pull your mobs away from his patrol path and not get agro. This area can potentially make you 45-80 World Of Warcraft Gold an hour.

Then there's the classic Hearthglen (north side, middle, of western plaguelands) elites of 55-57. They drop up to 33 silver but they hit my 4000armor plate for 150-200 damage and have about 7000 hp. It's also somewhat camped but generally is less camped than most other high end elites - you can easily find a spot of elites and safely solo if you pull correctly.

There's also Tyr's Hand located in the southeast corner of EASTERN plaguelands. These are 53-54 elites but hit for 220 on my 4000 armor plate. They also drop up to about 30 silver and rare items but it's often camped a lot.