By now I don't know if I could hope that there will be packs with many animals, this is not their policy, unfortunately there have been packs with a maximum of 8 animals, of which 2-3 completely new models and other remodeling of animals already present.
Perhaps the only pack potentially with many animals will be the bird pack, if there is one, but even on that I wouldn't be so sure.
If it were true that only 3 Planet Zoo DLCs remain, it would be a great regret because it is incomplete game, as there would still be many animals (especially monkeys of various kinds that are realistically very popular in zoos), a few exhibit animals, unimproved exhibit mechanics, playgrounds for children visiting the zoo nonexistent, many scenic and structural elements nonexistent, etc...