Playing since the SEA pack and the animals i haven used are
Grizzly Bear (Used HBB Instead as an EBB standin instead)
Zebra (Never build a big savanah habitat before + i prefer most of the antelopes)
Both Hippos (On the list of stuff that i want to build for big style, but first i gotta get to them)
All the Apes (while i had plans for the orangutan at some point, none of them have fitted into my zoos so far)
Thompson Gazelle and Spring bock (See Zebra)
Both Wildebeest (See Zebra)
Okapi (Havent build a tropical africa section before, also an animal i regulary forget that it is in the game)
Indian Elephant (Had plans for them in my first zoo, but got to big for my computer to run. Currently building/procrastinating the african elephants so props will take a while)
Pronghorn (Not particularry standout ish animal, also the modell looks kind of ugly)
Siberian Tiger (Only build once for tigers so far)
Giant Panda (I like building zoos inspired by those in the ruhr area and while great zoos (including the yearly winner for the best german zoo) none of them have pandas and while ive seen them before in berlin, they seem both to high profile and to much of a pain to build for)
Dingo, Koala, Platypus, Wombat (Till the emu and wallaby i never really had interest in building an explicit Australia area, only using kangaroos and cassowarys as inbetween habitats cause they are quite dope)
King Penguin (Got plans for them in my current zoo)
Giant Otter (Didnt fit spacewise into my SA section in my first zoo)
European Fallow Deer (My most anticipated animal for the game, but i havent gotten to use them yet eventhough i allready have plans for them in my current zoo)
Ibex (Very cool animal with the possibility for very specialised habitats that i allmost used but then kind of just didnt and have now put the racoon habitat in the planned space instead)
Proboscis Monkey (Funny monkey without zoo presence goes behind all those apes with zoo presence i havent used yet, especally the siamang)
Fenec Fox (Had plans in my first zoo, but like the indian elephant it got to laggy to reasonably build for them)
Southern White Rhino (Build for indian rhinos before, now elephants and hippos come first)
The entire North America Animal Pack besides the prarie dog (great animals but i prefer other cats, pinipeds, deer and crocodiles over them. That said i defenetly will build for the moose in the future with the beaver and arctic fox being on my checklist of animals i defenetly wanna build for)
Black and White Ruffed Lemure (lemures were my 5. habitat i ever build so while quite some time ago, no new desire to build another lemure habitat yet)
Capybara (I took a longer break before and after the wetlands dlc, literally just building a habitat for the red crowned crane, but these guys are planned for my current zoo)
Domestic Waterbuffalo, ASCO, Spectacle Caiman (Same as above but without any current plans)
Amur Leopard (Less cool then both Jaguar and Siberian Tiger)
SCO (Once a desert pack arives im sure they will be used, but they are among my top filler ungulates i still want to use)
Red Fox, Striped Skunk, Red Deer, Ninebanded Armadillo, Maned Wolf, Striped Hyena, Bats and Butterflies (I havent played since the twillight packs release and only started playing a bit last week where i started building a racoon, emu and wallaby habitat cause love <3. everybody else gotta wait)
Caracal (Seperated cause i propaply will put them in next once im done with the love trio)
Quite a few animals with most dlc animals up to the SEA pack being used and afterwards mostly just pick and choosing favorites of the new packs.
Another contributing factor was that my second zoo was made up of animal choices people in these forums gave me , even though ironically only the african penguin, red kangaroo and my choice of the giraffe where the only animals i havent used in my first zoo.
Hopefully i will have some more good sessions, so that i can also check the caracal, european fallow deer, king penguin and siamang quite soon