South Africa has many species that are common/uncommon in captivity that simply aren't present or extremely rare in other parts of the world.
1. Southern Reedbuck: This species is extremely abundant in the private trade, and are extremely easy to see by visiting a number of publicly visitable game ranches, other than that they are also on display at the Joburg Zoo.
The only other location in the world where you can see captive Southern Reedbuck is the Sharjah Safari Park in the UAE, which imported them from South Africa in 2017.
2. Cape Bushbuck: Not only is this species extremely common on game ranches but also terribly easy to see in the wild, With similar care requirements to the captively abundant Nyala, I can think of only one reason why they are so rare outside of Africa, being their aggression.
In South Africa, you can see Cape Bushbuck at Joburg Zoo, Warmbad Zoo, and the World of Birds Wildlife Sanctuary.
3. Common Grey Duiker: One of the largest duiker species, yet it was never established well in captivity outside of Africa, with simple easy welfare requirements, I don't see any reason for their underrepresentation other than their rather "boring" appearance.
Common grey Duiker can be seen in 8 South African collections.
Outside of Africa, only Sharjah Safari Park keeps them, imported alongside the Southern Reedbuck in 2017.
4. Bushpig: Considered a pest in South Africa, they are surprisingly uncommon in captivity here as well, with only 3 collections currently keeping them, and not present in the private trade, the European wild boar is far more sought after than their African counterpart.
Currently, only 1 collection keeps them, Warmbad Zoo.
5. Cape Grysbok: One of my favorite South African endemics, and sadly not all too common in the country, with no major zoos keeping them.
Exotic Animal World and Monkey town are the only public holders, they are present in the private trade as well.
6. Suni: Suni's only recently died out in American zoos, and are also not the most common species in South Africa, they are around in the private trade and were formerly kept at Johannesburg Zoo. Nowadays, only the Bothongo Lion and Rhino Park keep Suni.
7. Tsessebe: A species that has never been widely present in South Africa, both wild and captive. In recent years they have been introduced to many Private Reserves in the north of the country. To view them in a more captive environment, they are kept at Emerald Animal World and the National Zoo's satellite facility in Potgietersrus.
8. Aardwolf: Infamously hard to care for in captivity, In South Africa, they have shown rather good success surviving in a confined environment, and even bred at the National Zoo (which no longer keeps them)
Aardwolves are present in the private trade and are viewable publicly at Mystic Monkeys Wildlife Park and Bothongo Lion and Rhino Park.
9. Brown Hyena: With only two collections in Europe and a couple in Mexico, brown hyenas are by no means common in captivity, but in South Africa, they are rather abundant.
Publicly you can see Brown Hyenas at Eventieria Wildlife Park, Bothongo Lion and Rhino Park, Ann van Dyk Wildlife Cente, and Akwaaba Predator Park.
10. Purple-faced Langur: The purple-faced langurs in South Africa all originate from Stock imported from Europe in 2010 by Induna Primate and Parrot Park (A very private facility, not visitable by the public).
Eventieria Wildlife Park keeps a single female individual.