I wouldnt call most of the animals mentioned here forgotten but rather unflexible or hard to use.
The best example is the panda, cause they might aswell be a fantasy creature with the ammount of attention they need to feel fitting.
First of, if you care about realism at all having pandas in your zoo implies that its really stupid rich and important, so if you dont feel like building a supposedly world renowned zoo sky high budget zoo, they fall to the wayside.
Then they need alot of space, which also often is a turn off cause it means that the habitat will take a while, but cramping them just feels wrong.
And most damming, they are very handily replaced by a more realistic choice of bear or even red pandas, which need much smaller habitats and are more fun to build for.
This is a general trend, the more grand and important an animal feels, the more daunting they are to build for.
You cant just do a low effort or simple panda habitat, same for elephants, polar bears, gorillas, orangutans, king penguins etc. Smaller or less generally impressive animals come with the blessing of being more relaxing. Yes you can do a very elaborate and special and tricky ungulate paddock, but you dont have to so if you loose motivation you can just stop and have something decent looking to settle for.
Same for small animals like meerkats, they just are much faster. I build my meerkat habitat in 2 short sessions, roughly 2 hours total and it looks great.
My lion habitat also looks great, but that took atleast 15 hours, if not much more time to realise and even then it isnt particulary flashy.
Another example are gorillas and okapis. Directly next to each other, i pushed the okapi habitat out in 4 hours tops, a simple fun and relativly fast build with some small quirks which looks great and does it job. Meanwhile the gorillas have surly wasted allready 10 hours of my life away atleast as it required a good looking climbing frame, a good looking house as the holding with indoor viewing and a watchable custom food kitchen, signs for the different gorillas of the group, another house on a hill as a viewing gallery, another expansion i made cause it just "Felt right to do" cause there allready large habitat felt "to small" and once im actually finished with it its atleast 2024.
There simply are animals you dont want to halfass, animals that demand special attention and cant just be some nice filler and thats what makes their build rarer as other animals.
Think about it, what does your zoo or any zoo youve been to more of? "Filler" habitats or big special "headliner" habitats?
Im quite sure its the former and for good reason. And thats what makes animals that can work as filler so flexible and desireable and those that do the job the best like the red river hog, red panda, meerkat and lemures seen that often in peoples zoos.
I personally challanged myself with my current zoo from the get go that i wanted to sprinkle in some of these highprofile animals in, most notably the lion, elephant, king penguin and an ape just because in my older projects i was kind of to scared of actually integrating them into my builds, feeling much more compfortable with simpler animals like kangaroos, reindeer, pigs and the like, which are some of my most used animals by far.
But besides those, there are some animals that simply have great competition or saturation allready in the game.
Animals like the dhole or sable antelope, while having many great aspects in their own right, just arnt used because they have "better" competition, which is why i personally really dont like people asking for more of the same. If we have 12 cats, just being a cat does not cut it to stand out. One of the best examples is imo the dingo.
The dingo has many cool things about it in theory like being a naturalised apex predator and being for along time australias only terrestrial animal in the game, but people still did not use it.
At first its problem was a lack of australian options. There wernt actually that many canids when the dingo joined as it was only the 4. and as a yellow desert dog from australia pretty unique, but not many people actually build australia areas after the initial hype went down as they most often either used just the kangaroo and or koala for very small areas or just used the animals as general filler. At that point the dingo only had to compete with the african wild dog and 2 wolfs for possible random canid slots, but at that point most people wernt bored enough of continental themes to actually pick just whatever animal, so not being part of a popular area to build was kind of a death sentece for usage, combined with the fact that large canids arnt the greatest filler picks in the first place.
Once the wetland pack arrived, things actually got much better for the dingo. As we got drop fed australian animals 1 or 2 at a time last year, australian areas that were a bit more expansive came back into fashion, with leafs boggy bottons dingo build actually being the first ive seen since the australia pack hype. A few more people build modest australia areas or even australian zoos, were the dingo often was a nesseceary mostly dictated by the lack of options. It wasnt a commonly build for animal, but you saw it from time to time instead of just not like in most of 2021.
But now that the Oceania pack arrives, im quite sure that bit of dingo building will both go up and down.
The fact that oceanian zoos are even more possible now will propaply help them find a spot in them, as it still brings something very unique to oceania with a large pack hunting carnivore, but at the same time in none oceania focused zoos, im quite sure it will pretty much die out?
Why?
Cause this guy
The tasmanian devil is everything the dingo wishes to be. Its a high profile animal that adds australias first marsupial carnivore that can very easily be a highlight animal due to its uniqueness, rarity in zoos and status of being the largest maruspial carnivore, while also being quite flexible as they fit in nocturnal houses, outdoor displays, dont look to wrong in tropical houses, but also are a great filler pick. Im very sure that from now on the by far majority of players will use the devil over the dingo whenever they build for australian areas, which while still limited now have the freedom of choice to build a rather large one with 10 animals without including the dingo, which needs more space, is less unique and overall less desireable for most people.
And now to add insult to injury, the dingo isnt even complete with 2 of its most common and very unique looking colormophs, the black and tan and the cream, missing, aswell as it being the only gray wolf subspecies that did not get the chorus behavior.
And now adding even more damnation, it isnt even special as a canid anymore, as we are now very much saturated with them, with those that came after it having much better reasons to be added randomly aswell as to their respected areas, as the dhole and the 3 foxes are excellent filler animals and the maned wolf being very unique from other canids.
The dingo currently is stuck as the least desireable canid without anything setting it apart and even lacking features that other canids have that it really should have aswell.
The foxes are both more flexible and more essential to their enviroments, the maned wolf is unique both in looks and the fact that its not a pack animal, aswell as having the strongest niche for relevance in the game called being from south america, the dhole is the better filler animal and is among the most flexible animals in the game, the african wild dog is not only prettier then it but also from the continent that most commonly pops up in zoos (how many zoos without an africa section have you seen?) and then the arctic wolf is the pretty dog with chorus and also has the benefit of a starving biome that needs it as theres only so little representation and the original timberwolf, which is more flexible as its the main wolf and canid, but has a really underwhelming model, so its arguably the only one below it and even then i have seen many timberwolf builds, as even though its quality is ass the love for it never dropped of. The dingo suffers from being not just being unpopular, but also being outclassed greatly both in its taxonomic group and its continental niche, making it one of the few truly next to completly not used animals in the game. If its used its never for its own sake but because the person wanted a larger oceania area and ran out of option, something only growing less likly in the future.