There's a whole lot of ungulates I still want to see added to the game. Some are from Asia, some from Europe and North America, and some are from Africa. Here's some of my top picks:
1. Greater Kudu. I know that we already have a seemingly endless supply of African antelopes, but the Greater Kudu is very iconic in my opinion and is unique enough from the other African antelopes to warrant an inclusion. I think this species would be a perfect addition to our African safari sections.
2. Muskox. This is one of the last notable arctic species we still need, and we really don't have many caprids currently, so I think these are a must-have in the game.
3. Red Deer. We already have decorations for this species, and I feel like this species would help to give a little bit more European representation. I think the Red Deer embodies the majesty and beauty of ungulates more than any other, and I would be happy to see this species in the game.
4. Black Rhinoceros. This is, in my opinion, the last Rhino we truly need.
5. Dromedary Camel. What's a zoo game without the Dromedary? We also don't have a lot of North African/Middle Eastern animals currently, so I think the Dromedary would help to flesh out that region of the world in the game.
6. Blackbuck. This is a unique-looking antelope from southern Asia, and I think it would help to break the African monopoly on antelope species in PZ currently (as much as I love African antelopes, we need some Asian ones too).
7. Saiga Antelope. These funny-looking antelopes are very unique, bring in a conservation aspect, and are just pretty important to include imo. Another antelope from Asia as well, which is great.
8. Mountain Goat or Bighorn Sheep. While both of these resemble the Dall Sheep in some ways, I just think we need one more caprid from the mountains of North America, since the Dall Sheep is only found very far north and doesn't really represent North America's mountain ranges as a whole.
Honorable Mentions:
Yak
Wapiti/American Elk
A smaller deer, like the Muntjac
Any type of Hartebeest
Blue Wildebeest
Axis Deer
Sika Deer
Giant Eland / Common Eland
Takin
Chamois
Gaur
and many more!