I admit I haven't explored everywhere, and sometimes may have just briefly flown around. If any of these are well-known horde wise I apologize, or even if quests later in a zone take you there (not having done everything yet myself). As a side note I use TomTom for coordinates, in case they differ with any other addon.
The Jade Forest:
At 45/37 in the jade forest is a pond, in the center is a little wooden raft with a skeleton, a alien rag doll, and two birds that sort of move their heads around, amusingly enough at the bottom of the (seemingly shallow) pond are two oars.
I don't have the coords for this one but there is a run away cart that ran over its owner. I believe its near a road, and near a rare spawn point.
Two of the many mountains in jade forest are named Exclamation Point(29/35) and Spire of Solitude(27/33). Not particularly interesting, but it amused me.
52/13 is a house on a mountain top, the house has many balloons attached, inside is a grumpy pandarian named Kar, outside is a grummle named Rusty Nail and a fox named Dig. A reference to the movie Up.
An achievement spot for those that don't know is the Shrine of Fellowship 32/33 (this is where the walkway starts to the top) keep an eye out for anything clickable.
Martar the Not-so-Smart 54/32 or thereabouts, neutral elite non-rare mob drops Martar's Magnifying Glass, a trinket where on use “Summons Martar the Not-So-Smart to fight, adventure, and frolic with you.”
The Veiled Stairs:
The Secret Aerie (51/12). Its a quaint pond with a book in a boat (the book is near 60/8) and the long bridge/walkway leads to a small village home of the People of the Sky and hawk trainers. Without flying you have to go through the ancient passage way and take the cut off in the cave.
75/76 is the top of the stairs to nowhere, Mason's Folly. When I first went there a hammer was just laying on the ground, one of the grey 100g items. I can't remember the favor text, unfortunately.
On Mount Neverest near the top is a frozen mountain climber.
On the coast coords 43/17 is a little hut, outside is a hozen named Tik Tac, the Carpenter and inside the hut is Wally the tuskarr. You can ask him how he got to Pandaria and he has a few replies, the lines are basically from Alice in Wonderland, the story of the walrus and the carpenter.
Along the coast is a little cave (28/26) inside is a hozen Grohl Grohl the drum master.
Again along the coast is a flying turtle (about 54/20) named Lon'li Guju, if you /wave, /hug, or /love (possibly more) him he'll follow you around for a little while. I'm told this is reference to an actual tortoise named Lonesome George who was the last Pinta Island tortoise and died during MoP beta testing. He flies around so my location may not be where he actually is.
A neutral ram named Zhing wanders 38/53, one of the elites non-rare mobs you can kill for fun items. He drops a Bag of Kafa Beans which allows you to ride the large ram for a short while.
Vale of Eternal Blossoms:
This one I'm not sure what it references, if anything, but two large seemingly dinosaur like skeletons lie next to each other at 24/13 surrounded by roses.
32/13 is Loh-ki talk to him to get a little more info on the rare dragon Alani.
This may be a quest area, I'm not entirely sure. But 18/67 is an island full of frogs and near the beach is a little sign depicting a frog.
Valley of Four Winds:
In the valley are two named mobs, you might not give much thought to them but each drops a quest item. First is Krosh at 65/25 at the pools of purity, he drops Krosh's back (Kresh from wailing caverns, anyone?), this is lootable by any in the party. Second is Manglemaw at 56/25 in the Gilded Fan, his was only lootable by myself and not the other member of my party.
I'd like to know if anyone else has found anything interesting in Pandaria, of course you can always post some of the old world secrets, some people may not know about them just yet. Feel free to correct me if something is involved in a quest or if you know the reference.