Elephants, hippopotamus, rhinos, giraffe, zebra, lions, tigers, bears (oh my), polar bears specifically, a spotted big cat, kangaroo, a deer, a caprid, an antelope, a large bovid, penguins, a turtle or toise, crocodiles, camel, flamingo, ostrich, some kind of pig, panda, wolf, gorilla, a mandrill or baboon, and debatably otter and pinniped (though often locked behind expansions/dlc)
Large cats tend to be do pretty well in these games but I don't "expect" all of the spotted cats to appear simultaneously so kept it vague. There are definite trends with antelope but I also feel like a future game could launch with different choices and no fuss. Reindeer and walrus almost always represent deer, bison or African buffalo for bovids, but caprids vary. Okapi, Tapir and Snow leopard tend to be common but don't feel quite ubiquitous. Koala and Komodo have become more common since Zoo Empire, but since neither were in zt1 and zt2's base roster (I know about the xps) I tend to view them as 'bonus' more than 'expected'.
Meerkat and lemur would probably be ubiquitous but for some of the topdown simulators they disappear a bit.