If we are going with 8 i think a good mix would be:
- Cotton-top tamarin , one of the most common monkeys and animals in captivity in general. Very unique look, critically endangerd and very well studied, because they were a very common lab animal in the 60ths and 70ths. Also unique as they dont live in the Amazonas basin, but in columbia and the coastof the carribean
- Black tailed praire dog , Another extremly common zoo animal and a prime candidate for burrowing. Also one of the most iconic animals from northamerica from an outside perspective. Being a rodent is also a plus
- Indian crested porcupine, every one wants a porcupine and this species has the largest population in captivity by far. Their range from turkey, over arabia to india also makes them very adaptable in region and biome
- common genet, this mostly arboreal living relative of the binturong is common across all of its range stretching across all of africa and southwest europe, aswell as having a sizeable zoopopulation. These adorable nocturnal critters would be a joy to have and sit confortably in my top 20
- greater bilby, an australian exclusive animal, but one of the most common zoo animal down there and an icon of conversation, atleast if you would like to believe chudditch, our most vocal australian user. These guys are super cute and would be great to have for nocturnal houses or overall small dessert habitats.
- Alpine marmot, rounding out the continents these chonkers are again common in captivity, aswell as one of the largest rodents in general. They would also add an iconic alpine animal, as severly lacking biome in the game right now
- Prevosts squirrel, a colorful squirrel from indonesia and one of the most commonly held squirrels in captivity. They arenot only beautiful, but would also offer some much needed aboreal mobility
- Mountain hare, the eurasian equivalent of the snowshoerabbit, these hares live in the tundras of northern asia and europe, aswell as the alps. Being the most social of all hares they are a great fit and their changing fur color could be a cool edge that brings them over other rabbits and hares
With that selection of animals we have every continent and major biome represented, as well as introducing 4 very unique rodents to the game, as well as 4 miscelanous picks of other families. Also its an actually list of very small animals, with the porcupine and the marmot being the largest on the list