So I agree with most that we definitely need a large aviary and aquarium expansion, but I also like the two DLCs we have so far. Assuming they will continue releasing DLCs in the same style (4 habitat animals, a new theme and some foliage), I thought about options for future DLCs, based on animals that are really missing from the game, architectural styles and pieces that could be a great addition and types of exhibits we don't have yet. I came up with the following ideas that I think would be fitting for new DLCs in the usual style.
Australian DLC:
Animals: Red Kangaroo, Emu, Koala, Black Swan, (Frilled Lizard)
Construction: Australian Theme (Aboriginal-styled items, mosaic items)
Nature: Outback rocks, red forest gum, cabbage tree, kangaroo paw plant, rainbow eucalyptus, New Zealand flax, totara
Arabian DLC:
Animals: Nubian Ibex, Caracal, Hamadryas Baboon, Fennec Fox, (Egyptian Cobra)
Construction: Arabian Theme (Arabian-styled buildings, mosaic items)
Nature: Lebanon cedar tree, Socotra dragon tree, European olive tree, lavender, pomegranate tree, ghaf tree, Syrian juniper
Southeast Asian DLC:
Animals: Bornean Clouded Leopard, North Sulawesi Babirusa, Lar Gibbon, Binturong, (Reticulated Python)
Construction: Southeast Asian Theme (based on temples and traditional (floating) fillages)
Nature: Rafflesia, giant banyan tree, durian tree, Attenboroughs pitcher plant, giant bamboo, cananga tree, giant elephant ear plant
North American DLC:
Animals: American Alligator, Moose, American Beaver, Canadian Lynx, (Arizona Coral Snake)
Construction: North American theme (Native American-styled buildings, possibly western-styled?)
Nature: Giant sequoia tree, weeping willow tree, pond cypress tree, sugar maple tree, Florida palm tree, paurotis palm tree
Coastal DLC:
Animals: California Sea Lion, Southern Rockhopper Penguin, Sea Otter, Great White Pelican
Construction: Coastal theme (harbour-themed objects, possibly buildings like lighthouses, piers etc.)
Nature: Giant kelp, sea grass
Nocturnal DLC:
Animals: Striped Hyena, Three-toed Sloth, Nine-banded Armadillo, Honey Badger, (Cave cricket)
Construction: Walls and lights for nocturnal houses, darkened windows, darker pathways.
Domestic DLC:
Animals: African Pygmy Goat, Shetland Pony, Muscovy Duck, Domestic Rabbit, (Red-eared Slider)
Construction: Farm theme (farm-styled items for petting zoos)
Facilities: Playgrounds, playful information signs.
Australian DLC:
Animals: Red Kangaroo, Emu, Koala, Black Swan, (Frilled Lizard)
Construction: Australian Theme (Aboriginal-styled items, mosaic items)
Nature: Outback rocks, red forest gum, cabbage tree, kangaroo paw plant, rainbow eucalyptus, New Zealand flax, totara
Arabian DLC:
Animals: Nubian Ibex, Caracal, Hamadryas Baboon, Fennec Fox, (Egyptian Cobra)
Construction: Arabian Theme (Arabian-styled buildings, mosaic items)
Nature: Lebanon cedar tree, Socotra dragon tree, European olive tree, lavender, pomegranate tree, ghaf tree, Syrian juniper
Southeast Asian DLC:
Animals: Bornean Clouded Leopard, North Sulawesi Babirusa, Lar Gibbon, Binturong, (Reticulated Python)
Construction: Southeast Asian Theme (based on temples and traditional (floating) fillages)
Nature: Rafflesia, giant banyan tree, durian tree, Attenboroughs pitcher plant, giant bamboo, cananga tree, giant elephant ear plant
North American DLC:
Animals: American Alligator, Moose, American Beaver, Canadian Lynx, (Arizona Coral Snake)
Construction: North American theme (Native American-styled buildings, possibly western-styled?)
Nature: Giant sequoia tree, weeping willow tree, pond cypress tree, sugar maple tree, Florida palm tree, paurotis palm tree
Coastal DLC:
Animals: California Sea Lion, Southern Rockhopper Penguin, Sea Otter, Great White Pelican
Construction: Coastal theme (harbour-themed objects, possibly buildings like lighthouses, piers etc.)
Nature: Giant kelp, sea grass
Nocturnal DLC:
Animals: Striped Hyena, Three-toed Sloth, Nine-banded Armadillo, Honey Badger, (Cave cricket)
Construction: Walls and lights for nocturnal houses, darkened windows, darker pathways.
Domestic DLC:
Animals: African Pygmy Goat, Shetland Pony, Muscovy Duck, Domestic Rabbit, (Red-eared Slider)
Construction: Farm theme (farm-styled items for petting zoos)
Facilities: Playgrounds, playful information signs.