In Warlords of Draenor, seven rares drop a unique mount with a 100% drop. This means you can join in on any part of the kill and still loot the mount, just like any other Draenor rare. The only exception is Nok-Karosh who only drops one Garn Nighthowl per kill. For this reason, he’s often killed in groups or even raids so everyone has a chance to roll. Note: This mount is unbound so can be traded or sold in the auction house.
The other six have been described as the time-lost versions of Draenor (though easier to find) and if you’ve ventured into the Time-Lost Glade in the north-eastern part of Nagrand, you may have spotted a familiar name.
Unlike it’s counterpart in the Storm Peaks of Northrend, this one remains frozen in time so don’t bother camping this particular spot.
Now onto the good stuff.
Pathrunner in Shadowmoon Valley has 6 spawn points (including 56.3, 53.0) and a spawn time of ~5-16 hours. He drops the Swift Breezestrider.
Slithide in Talador has 5 spawn points (including 55.4, 81.8) and a spawn time of ~12-28 hours. He drops the Sapphire Riverbeast.
Luk’hok in Nagrand has 5 spawn points (including 66.7, 42.9) and a spawn time of ~12-28 hours. He drops the Mottled Meadowstomper.
Nakk the Thunderer in Nagrand has 5 spawn points (including 50.4, 34.0) and a spawn time of ~15-28 hours. He drops the Bloodhoof Bull.
Poundfist in Gorgrond has 5 spawn points and a spawn time of ~48-142 hours. He drops the Sunhide Gronnling.
Note: spawns may be affected by phasing due to multiple realm instances.