I have zero from any of these collections and have never seen any on the bazaar. I think they are not dropping and/or not spawning. If anyone has actually marked off any part of any of these in their achievements feel free to report. Restlessly Shattered (EW) Unfit for Adventures (velks) Trash from the Past (velks) Chilly Critters (kael)
They drop from the hero missions only so they are extremely rare. I have seen all of them drop (well not 100% on velks i have seen one of them drop) but the big problem with velks is they drop during the fights and if you win the corpses poof and u can't get the item from advance loot because the corpse with the item is gone.
I have 4 of the chilly critters sitting in my bag right now. Unfortunately they are only dropping off AoW himself, no other mobs in the mission. I have not seen any from the other missions, however.
Yes 3 of the ones u have listed i have seen items from them drop in hero missions. The only questionable one is the 2 in velks. I have only seen 1 of the 2 drop during hero.
I have heard it speculated that when a pet gets a kill shot on AoW, the collect it *may* drop will be unlootable. I have a pet heavy group of friends and we have seen around 8 drop and only able to loot 1. While other friends with no pet groups have had no issues looting them.
Yes, I dont have any myself but I have seen them drop in the missions. The issue of course is that the drop rate is the normal drop rate you get from kill type collects, and there simply are not that many mobs to kill in the missions, the consequence being that these particular collects are extremely rare, to the point that I think very few people will actually complete the sets.
As far as I can see with the Kael and Velketor sets at least, killing mobs yields the groundspawn collections for those zones. I've seen plenty of collects drop in the Velks mission, but they're always from the Useless Tools set and not the Unfit for Adventures or Trash from the Past sets. Killing the trash that is up at the beginning of the mission yields the same.