Been getting many of these off of the Minotaurs in near and in the Minotaur Mine in Dragonscale Along with Soluable Loam (RARE) drop have killed many mobs there EXPing many different alts for key parts to mansion, and faction quests.
I have had these drop off A blighted Cave Rat in dranik hallows watering hole and the murkglider instance while doing MULTIPLE sig runs for lots of guildies.
also have seen this drop off the swarms of mobs randomly in PoTime B beginning of Phase 4 while clearing .
Also have seen the drop from Rift Seekers Sanctum at statue camp.
Please, Please never ever make the Belt, Cloak, Pauldron, Gorget, and Visor Templates!!!
Its a huge waste of your time and cobalt ores because as soon as you make it, it becomes worthless except for your one skillup attempt you got. Instead, make the items that other Cultural Tradeskillers need, such as Bracer, Sleeve, Helm, Boot, Gloves, Leggings, and Breastplate.
If you make those templates instead, you can sell them in bazaar to the people who have completed the Cultural quest for their race and have the bag of molds. That way you still get your one skillup attempt but now you got a huge stack of templates that have some value. Those can be turned into the Elaborate line of plate and chain armors by Cultural tradeskillers. Since you have done half the smithing already, it cuts down on the supply of Cobalt Ore that is needed for the finished product.
For details on what I am talking about see my post under 'Elaborate Stalwart Cuirass'
Also dropping in TBS while we were hunting drops for Hand aug.Ore was dropping off raptors,panthers and basilisks and assume will drop off any other mob.