Alright, let's give this a whirl.
Asia seems to be next on the DLC list and since the Sun Bear was leaked a while back, I'm not including it on this list (I wouldn't have anyways):
1. Clouded Leopard - I see this animal on almost everybody's concepts for an Asia-themed pack, and I can't blame them! This small cat is very pretty and could make some really interesting habitat set-ups.
2. Northern White-Cheeked Gibbon - Gibbons are an iconic part of South-East Asia's primate line-up and I'd take any species found in captivity. I just find this species most appealing from a DLC perspective.
3. Binturong - Gets on this list over the Przewalski's Horse and Malayan Tapir purely because it's my favourite animal of all time.
4. Asian Small-Clawed Otter - I think that this animal is different from the Giant Otter in enough ways that could warrant it's addition. The most striking of which, is it's small size.
5. King Cobra (Exhibit) - If we were talking with larger exhibits in mind, I would go with the Reticulate Python. But we're not, so I'm settling for the next best thing, the longest venomous snake.
Africa has so many animals to choose that would really add to the game in my opinion, so it's hard to choose only 5 (technically 3 as 2 species are pretty much absolutely necessary):
1. Black Rhinoceros - I'd take either species (Heck, I'd take both) but it'd be nice to see some more critically endangered animals in the game (there are only two DLC animals that are below the vulnerable status)
2. Meerkat - Kind of obvious, but the meerkat is found in most zoos around the world. Plus we need some more smaller animals to help fill exhibit gaps.
3. Fennec Fox - Another small animal idea. This probably the best fox species to choose as they actually feel like a zoo animal, plus add to the desert biome which could use some more exclusive animals.
4. Hamadryas Baboon - There are so many other animals I could've gone with for this one (Secretary Bird and Addax were the most painful exclusions), but we could use some more monkeys. This species is unique because it's a desert monkey, of which there are few. I also seem to see this one a lot in zoos so there's also a bit of bias on my end.
5. Panther Chameleon (Exhibit) - We still need more lizards. End of discussion.
North America has a lot potential for some "clone" animals, but I'm going to try and focus on some of the more unique species here:
1. Moose - The largest deer in the world... is not really a zoo animal. But it's iconic as a zoo
game and is found in some zoos so it gets a pass from me. I just find it too iconic to not end up including in either a North America or Europe pack (Preferably NA for me though).
2. American Beaver - We can easily throw in more diving animals after the Aquatic Pack, in fact 3 are in this country's list, so why not beaver?
3. American Alligator - Easily the most clone-like of all the animals on this list, but I don't care. I'd like to do a reptile-themed zoo in the future and I can't really do that without a gator, they're in some many places (I wouldn't be surprised if it's the most common crocodilian in captivity).
4. California Sea Lion - Should've been in the Aquatic Pack, but maybe they were saving it for a NA Pack? Arguably one of the most iconic animals when people talk about marine animals for zoo games, they're just so common and interesting.
5. Axolotl - This critically endangered little amphibian could help add to the new aquatic based exhibit AND is very popular (we kind of need that for DLC exhibit animals unfortunately. R.I.P. my dreams of hissing roaches).
Europe has very little when it comes to new animal selections in my eyes, but I have managed to wrangle a pack idea together in the past, so I'll use that here:
1. Alpine Ibex - Represents the alps and mountain ranges of Europe. Probably guaranteed for this type of pack as it was in the base roster for both the Zoo Tycoon games (similar to the Black Rhino from earlier). Adds to the caprid variety.
2. Iberian Lynx - I would be cool with the Eurasian species, but this endangered feline is my choice mainly due to its status and that it represents another unique biome, the Mediterranean.
3. Red Deer - Sort of a "it's just there" pick for me, but people seem to want it. I do like the idea of putting it in a gardens type are of the zoo though.
4. Wolverine - Hah! I cheated the system! This is an animal that I want for North America, not Europe! But it's still found in Europe so I put it here so we can get more NA animals while still not breaking the rules.
5. Fire Salamander (Exhibit) - Honestly, more amphibians would be great. And the Fire Salamander is basically the quintessential salamander without feeling boring somehow. Plus, it looks like a lizard, so it gets double points from me.
Despite the Australia pack existing, we still have a decent amount of animals to cover from Oceania as a whole that could be worthy of a slot:
1. Emu - I like the cassowary, but the Emu is far more common in captivity and I just really want one. I'd like to have a good zoo game with an emu in it. I got my wish with the cassowary, but the emu is still waiting.
2. Tasmanian Devil - The most disappointing exclusion from the Australia Pack in my eyes, people always overlook Tasmania despite it being part of the same country. This endangered and carnivorous marsupial would add to my theme of small carnivores that I have been slowly building up without you people noticing. I shall build an army and it shall be glorious! Wait- where was I again?
3. Southern Hairy-Nosed Wombat - This is probably my oddest choice yet, but wombats are cool, so here it is.
4. Matschie's Tree-Kangaroo - I had to shove in a non-Australian species in here somewhere (even if it's at the expense of a wallaby getting included

). Tree-Kangaroos are in a decent number of zoos and most are fairly endangered, plus they're tree-kangaroos. I feel like that's a bit contradictory but hey.
5. Frilled-Neck Lizard - I personally wanted this over the blue-tongue but we can have both, right?
South America, despite being one of the most diverse continents species-wise, we're still lacking some really interesting species:
1. Capybara - This one is obvious, everyone has been clamouring for this animal since the South America Pack got first teased. And then we didn't get it. And then the Aquatic Pack was announced, and had more South American animals, and we still didn't get it despite having water be very important to the species. I think it's about time we got this large aquatic rodent.
2. Maned Wolf - We really need some more diversity in the dog shapes in this game.
3. Humboldt Penguin - More of a zoo animal than the King Penguin really.
4. Geoffroy's Spider Monkey - More New World monkeys would be excellent. I personally find spider monkeys more interesting than howlers however (would still like both though).
5. Hercules Beetle - If we were talking about bigger exhibits, the Green Anaconda would easily make the list. But since we're not, the Hercules Beetle will do. I would've preferred this over the Titan Beetle, which is the only animal in the game that cannot be kept in captivity (only adult males have been so far apparently, they're that rare), and honestly? The Hercules is far more interesting in appearance anyways.