Ironically, I think I've seen snow leopards show up the most often in zoo games out of all the spotted cats. As for otters and seals, I feel like you can still generally expect them, even in games that lack marine expansions.
I also feel like you can generally expect koalas and Komodo dragons, since koalas are the second most popular Australian species after kangaroos, and Komodo dragons are most commonly occurring reptile species (crocodiles and turtles show up in practically every zoo game as well, but the depicted species usually varies).