Everyone one of the quests below I had missed the first time going zone to zone (in Kalimdor):
The Barrens (10-25)
Gilthares Firebough: There is, since BC, a new Blood Elf NPC located in one of the towers of Northwatch Hold that starts an escort quest titled 'Free From the Hold.'
Pilot Wizzlecrank: In the Venture Co. drill site in the Northern Barrens is a goblin who starts a short escort quest titled 'The Escape.'
Silithid Harvester: You probably know about Owatanka, Lakota'mani, and Washte Pawne from the Southern Barrens, but there is a fourth mob I've only ever encountered once while questing. It's in the field of giants, mixed in with the other Silithid.
Stonetalon Mountains (15-27)
Piznik: At 71,60 in Windshear Crag, Stonetalon, there is a cave containing a goblin who has you escort him around while he mines ore, then has you deliver it to Ziz Fizziks (the goblin in the hut).
Ashenvale (18-30)
Ursangous: In Ashenvale there is a named bear which wanders around the area East of Mysral Lake. He's usually around 40,65. The bear is part of the 'Ashenvale Hunt' quests, but was definitely the hardest one of the three for me to find. He drops his paw which starts the quest.
Diabolic Plans: This item drops off the demons in Felfire Hill, Ashenvale. It starts a quest (of course!). If you've already done 'Destroy the Legion' out of Splintertree, you may have picked this one up as well. (Only remembered this one because I got the drop today doing that same quest)
Desolace (30-40)
Rackmore's Log: In Desolace at 36,30 on the coast is a book which starts the quest 'Claim Rackmore's Treasure!' Northeast of this log by the tower is a quest giver that starts a short chain of their own.
Flayed Demon Skin: The Burning Blade mobs in Thunderaxe Fortress in Desolace have a chance to drop this item, it starts a short quest.
Dustwallow Marsh (35-45)
Loose Dirt: This one is fairly common to have done I think. There's a pile of dirt next to a house at 55,26 in Dustwallow Marsh. It actually starts two quests for the Horde though, so make sure you've done both 'The Lost Report' and 'The Severed Head.'
Feralas (40-50)
Pristine Yeti Hide: You know the deal, rare drop off the Yeti in Feralas, located around 54,32. This item starts a quick hand-in quest.
OOX Distress Beacons: There's three of these, one for Tanaris, one for The Hinterlands, and one for Feralas. They're rare drops, and start an escort quest, after completing them all you get a quest to go to Booty Bay and receive a free chicken non-combat pet.
Tanaris (40-50)
Map Fragments: Occasionally lootable from the Pirate's Footlockers that the Southsea Pirates in Tanaris drop. Also appear on the AH sometimes. If you collect all three pieces you can assemble them to get a quest for Cuergo's Gold.
Ship Schedule: Also a drop from the footlockers mentioned above. Starts a short hand-in quest.
OOX Distress Beacons: There's three of these, one for Tanaris, one for The Hinterlands, and one for Feralas. They're rare drops, and start an escort quest, after completing them all you get a quest to go to Booty Bay and receive a free chicken non-combat pet.
The Hinterlands (45-50)
OOX Distress Beacons: There's three of these, one for Tanaris, one for The Hinterlands, and one for Feralas. They're rare drops, and start an escort quest, after completing them all you get a quest to go to Booty Bay and receive a free chicken non-combat pet.
Venom Bottles: They're just laying around in a few of the Witherbark camps in The Hinterlands, picking one up starts a quest chain.
Azshara (48-55)
Captain Vanessa Beltis: The only time I ever tried to do this quest it was bugged. That was over two years ago though, so maybe it works now. This NPC is located at 53,87 in Azshara, she has you defend her against Naga. The coolest thing about this quest (bugged or not) is exploring the sunken ship.
Kim'jael: At 53,21 on top of a huge hill in Azshara (approach from the North) is a goblin that begins a two-part quest chain.
Silithus (55-60)
Brann Bronzebeard's Lost Letter: Rare drop off Silithus bugs, starts a quest, blah blah.
Azshara - 53, 21. There is a goblin who has a quests taking you into the Blood Elf camp, and a follow up sending you into ruins to kill random naga to get an item 'Some Rune.'
Feralas - The Gordunni Outpost above Mojache. There's a scroll on the ground there. This one actually has about 2 or 3 quests afterwards.
Mulgore - In the starting area, where the Quilboar are, there is a cave called 'Squealer's Cave.' Inside is a scroll.
* Also in Mulgore is a rare spawn, white wolf called 'Ghost Howl' who drops a quest item. Mind you, this is like, an 8 hour spawn. He wanders around Thunderbluff. I found him on the western side.
Durotar - The lookout tower on top of the western hill outside of Razorhill has a quest. Likewise, there's a farm with some pools of what around it at about 43,30 with another quest that's easy to miss.
Thousand Needles - Okay, this one was a life-giving. It's called the 'Test of Faith' and it's a chain that's about 10 quests long. Takes you many places, including the eastern Kingdoms, but they all count towards Kalimdor.
* Look for the 'Galak Messenger' who wanders around the North western areas of Thousand Needles. He drops an assasination note. This has a followup quest too.
Also see
http://forums.worldofwarcraft.com/thread.h...=11621243&sid=1 for a big ass list of easy to miss quests.