Came across an old archived guide from MMO-C while looking into TBC and figured I'd share here!

So ... You like shiny resellable loots and the thrill of hunting big animals with oversized guns at the potential cost of your life ?
Farming rare mobs is for you !

You can farm two kind of monsters :

• Normal rare monsters
  Most of the time they are just normal monster with a bit higher stats. They are easily soloable but you won't find them often even if you know where to look, most of the time anyone seeing one of these free loot dispenser will kill him without further thinking.
  But it's still nice to check their spots when you pass-by.
• Rare Elite monsters
  Basically, they're the same as the normal ones, but you will certainly need a group to kill them (except for the few ones you will manage to kite). The good thing is that people won't bother killing them as often as normal ones, they're too lazy to build a group just for one monster.
  Get your own group, scout all of them, and share the loots !

Normal Rare Monsters (Solo)

They are soloable, but you won't find them except if you're lucky (and know where to look, this is why you're here).They've got nearly-normal monsters stats, therefore I won't add tons of informations about them, it would take you more time to read everything than to actually pull and kill the mob.
Will only be shown on maps by an orange dot, except if they've got quite a long roaming route.

Hellfire Peninsula
Mekthorg the Wild - Hellfire Peninsula
Location : Near Hellfire Citadel or Zeth'Gor.

Zangarmarsh
Coilfang Emissary - Zangarmarsh
Location : Around one of the four steam pumps. Can be a bit tricky because of the frostbolt/arcane explosion it does, but still easily soloable.
Bog Lurker - Zangarmarsh
Location : Umbrafen/Feralfen/Daggerfen Village.



Terokkar Forest
Okrek - Terokkar Forest
 Location : Veil Reskk/Shienor/Skith/Shalas
Doomsayer Jurim - Terokkar Forest
Location : Roaming near Shattrath and Firewing Point. This one is a warlock, he uses incinerate/shadowbolt/fear. Just make sure you're full life/mana before engaging him. Be careful if he's near Shattrath, it seems he can be aggroed and killed by guards (bye bye loots !).
Crippler - Terokkar Forest
Location : Pretty much everywhere in Bone Wastes/Auchindoun. Harder to kill him as a melee class because of the high armor buff he get when he reaches 50% life.


Nagrand
Goretooth - Nagrand
Location : Most of the water places in Nagrand. He can be underwater so he's one of your best chance to get a rare monster if you're looking for them, but keep in mind that he's the only crocilisk of the whole region so he's still easily spotted.
Bro'Gaz the Clanless - Nagrand
Location : Roaming in Nagrand, see map.


Netherstorm
Ever-Core the Punisher - Netherstorm
Location : Circling around Manaforge B'naar/Ara/Ultris.
Chief Engineer Lorthander - Netherstorm
Location : Manaforge Ara / Ultris / Duro. Instead of Ever-Core, Lorthander can enter Manaforges and could be a little more harder to find, he look likes a blood elf with a staff (which isn't really easy to spot in these zones)


Shadowmoon Valley
Ambassador Jerrikar - Shadowmoon Valley
Location : Illidari Point/ Eclipse Point / Netherwing Ledge / Ruins of Baa'ri.

Elite Rare Monsters (Group)

They are group encounters, you won't kill them alone except for a few you can kite while you kill him ... or just kite him to the nearest town and pray to get the loots, but it would be very unethical of you to do this.
I suggest forming a group when you're finished raiding or something like this, and don't know what to do. It will takes a few minutes to scout all of them and you may end with one BOE rare for each player.

Hellfire Peninsula
Fulgorge - Hellfire Peninsula
Big earth worm with basically the same abilities as his friends, he will go underground and repop at a random location near you.
He seems to be roaming randomly following three straight lines through Hellfire Peninsula

Zangarmarsh
Marticar - Zangarmarsh
Marticar is a strider, he doesn't hit very hard but has a nasty ray that could damage you a bit. But as all the other rare elite, there's really nothing you can't handle.
He seems to be roaming randomly following three straight lines through Zangarmarsh


Blade's Edge Mountains
Hemathion - Blade's Edge Mountains
Big drake. You will only find him in the flying mount accessible zone, west of Blade's Edge Mountains. He's immune to fire but won't cause you much problems as long as you've got the classic Decent-Tank/Healer/DPS combo. He drops rare breastplates.

Morcrush - Blade's Edge Mountains
What a surprise, a stone giant that splits when you damage him. Like any other stone giant he will use a war stomp and split into an add every 25%. Possibly the most easily kittable rare elite. Only problem is, like Kraator, he can spawns everywhere in east Blade's Edge so it's hard to fast-scout him.


Netherstorm
Nuramoc - Netherstorm
Standard Chimaerok, he may (poison) spit on you if you're not nice with him.
He seems to be roaming randomly following three straight lines through Netherstorm


Shadowmoon Valley
Kraator - Shadowmoon Valley
Some kind of red inferno guy, he can summon adds and may conflagrate during the fight. Sounds like an impressive fight, but as other fights, it's nothing a group of lvl 70 can't handle easily.
Can spawns nearly everywhere in Shadowmoon, pain in the ass to look for him.

Collidus the Warp-Watcher - Shadowmoon Valley
Big eye. This one loves dealing elemental damage with a ray that may kill your tank if you don't have proper healing. Nevertheless, it should be easy as long as you've got a tank, a healer, and a dps class. Be careful if you're not using a warrior to tank, he can fear and he may rush healers / DPS classes while your tank is running around screaming like a girl.
He seems to be roaming randomly following three straight lines through Shadowmoon Valley (what a surprise.)

Originally from MMO-Champion (archive.org)