Desolace Quests

For Horde Loremaster achievements:

List of quests:

Starts with Cenarion Researcher Korrah @ Ethel Rather:

The Emerging Threat
Slitherblade Slaughter
Going Deep
Wetter Than Wet
Deep Impact
Mystery Solved
The Enemy of Our Enemy
A Revenant's Vengeance
Return and Report
Official Assessment
Naga Threat completes

Go to Karnum @ Karnum’s Glade:

From Karnum Marshweaver:
Stubborn Winds
(He won’t give you any more until you do Thressa+Ferrah’s quests, see below)

From Thressa Amberglen:
Blood Theory
Calming the Kodo

From Botanist Ferrah:
A Time to Reap
Pulling Weeds
Taking Part

Back to Karnum Marshweaver:
Ghost Walker Post
Delivery Device
Maurin’s Concoction
Cleansing our Crevasse
Threats from Sar’theris Stand completes

Completing Thressa+Ferrah’s quests this will also make another quest pop up which starts from Garren Darkwind:
An Introduction Is In Order
Cenarion Property

From Khan Leh’Prah:
Breakout!
Delicate Negotiations
Will Work For Food
My Word is My Bond
Karnum's Glade completes

Continues From Khan Leh’Prah
Three Princes
Not So Fast!
While You're Here
Behind Closed Doors (drops from a Maraudine Mauler while doing “Not So Fast!” also, when doing this quest you will see a thing to the side offering “While you were Here”, you can do this back outside while killing Maulers but not required for Loremaster)
Time For Change
Into the Fray!
Death to Agogridon
Uniting the Tribes completes

From Karnum Marshweaver again:
Shadowprey Village
@Shadowprey Village
From Mai’Lahli:
Blubbergut
From Jinar’Zilen:
Fish in a Bucket
From Talga Wisemane:
Chipping in
On Behalf of the Horde completes

ALL DONE. Everything else are side quests.

Drop Quest From Thunderaxe Mobs: Ears Are Burning
Bizby: [npc=35757]
Thunk: [npc=35661]
Ancient Tablets: [object=195433]
Malyk: [npc=41487] (gives you a quest to go to Desolace)

There was at least one more drop quest but I can't, for the life of me, remember what it was from. Centaurs maybe?

Welcome to the hardest zone for the loremaster achievement. The mobs that need to be killed for many quests are scarce and spread far apart. The quests are really grindy. After you finish all the tedious and wristslitting quests, you can enjoy spending 30 minutes scraping 3 or 4 more quests to finish it off.

Good luck have fun :)