African Animal Pack
White rhinoceros
Meerkat
African leopard (would've preferred Amur but that ship has sailed)
Hamadryas baboon
Grey-crowned crane
Red river hog
Crested porcupine
This pack feels absolutely stacked with heavy hitters and essential animals. The red river hog and crowned crane are very striking animals, while the rhino, meerkat, leopard, and baboon are all absolutely essential for the complete zoo package. I almost included the greater kudu over the porcupine, but ultimately I opted for the more visually distinct animal. I could easily fill out a second and probably even a third African pack without even starting to exhaust the incredible biodiversity the continent offers, though.
Americas Animal Pack
California sea lion
Mountain lion
American alligator
Moose
Tamandua
Capybara
Maned wolf
This one feels like cheating a bit, but I think it's pretty important. I could easily come up with a full pack of 7 for each America, but I also think that these are the priority species. The moose I'm a bit on the fence about... It's a Zoo Tycoon classic and the community seems to want it, but it's not actually all that common of a zoo animal from my experience. I'd much prefer a beaver, raccoon, or even American black bear in that slot, but I think moose is still probably the way to go.
Small Mammals Animal Pack
Fennec fox
Fishing cat
Golden lion tamarin
Brown-throated three-toed sloth
Matschie's tree kangaroo
Giant armadillo
Coatimundi
This pack is absolutely essential even if most of the individual animals themselves are relatively interchangeable. It's already gone through multiple revisions as I've typed this post: I've swapped the armadillo, coati, sloth, and tamandua in and out of the Americas pack, I've toyed with including wombats, Patagonian maras, prairie dogs, rock hyraxes, different lemurs and small cats, fossas... Ultimately, though, the bottom line is that we need far more "lesser" animals than we presently have. They're so crucial in making zoos feel realistic, yet it feels like we have so few of them currently in the game. The only ones that really fit this category are the current lemurs, capuchins, red pandas, pangolins, and the upcoming binturong and clouded leopard. We need more variety. These are so often the animals I end up spending the most time at in zoos too, so I'm absolutely starved for more variety.