Found this out today and thought I’d let people know that they can’t just buy everything off the AH this time around.
I had a Brinestone Algan (https://www.wowhead.com/npc=154845/brinestone-algan) drop from Avarius in Nazjatar, and upon seeing it had a “1/1” count on it (meaning you can only have 1 in your collection, which is typically reserved for special pets), I opened my pet journal, and low and behold, found it couldn’t be caged.
I ended up doing some research and found this isn’t the only case. There’s one other rare in Nazjatar that drop an un-cageable pet:
Rockweed Shambler Drops the Budding Algan: https://www.wowhead.com/npc=154846/budding-algan
Avarius Spawns around 36, 11 inside of the Cave. It requires the Brimstone Pickaxe item, which is a zone drop. If you have it, a glowing rock will be in the cave if it is available to summon. If it is, click it, and a bunch of crystals will spawn around you. Then you have to mine the Brimstone in the cave to find 5 unique colored Brimstone crystals to socket into the slots to summon Avarius.
Rockweed Shambler has a chance to respawn in place of any Lost Algan and Wayward Algan in the zone… so finding it is pretty much all up to luck.
Obviously, neither pet is a 100% drop.