I'll go ahead and write down some of my own ideas

I thought of some free update ideas, but not for all of them.
Birthday: Dromedary
Autumn 2022: Woodlands DLC
Gives more love to temperate forests around the world. No exhibit animal this time.
Free update comes with playground items for kids. These are items you place down like benches, that kids want to interact with and which gives them happiness.
- Red deer
- Wild boar
- Raccoon
- Skunk
- Red necked wallaby (Bennett's wallaby)
- Common wombat
- Wolverine
- Mouflon
Winter 2022: Submerged DLC
Introduces fully aquatic animals and a new exhibit type (tank). Comes with a marine theme, and lots of corals and underwater plants.
Free update includes new exhibit sizes, and provides a few fish species for tank exhibits.
- West Indian manatee
- Arapaima (giant freshwater fish and obligate air breather, which means it needs to come to the surface to breathe)
- Sea turtle
- Manta ray
- + Jellyfish
Spring 2023: Drylands DLC
Gives more love to arid regions in the world.
Free update includes changes to the sandbox animal market, which gets an added 'custom animal request' tool where you can request the animal with the stats and appearance of your desires.
- Addax
- Patagonian mara
- Collared peccary
- Caracal
- Emu
- Hamadryas baboon
- African crested porcupine
- + Cobra
Summer 2023: Islands DLC
Gives more love to island life around the world. Comes with a tropical island theme, and foliage from Tasmania and Oceania tropical foliage.
Free update comes with a gene bank, so you can save the sperm ("essence") of males in your zoo, so you can still use them even after they are gone. This will be very nice for maintaining breeding programs.
- Tasmanian devil
- Coconut crab (giant land crab)
- Fossa
- Goodfellow's tree kangaroo
- + Giant moray eal (the kind that divers lose their arms to...)
Birthday: Red fox
Autumn 2023: South America animal pack.
Revisit to South America to flesh it out with more animals.
Free update gives all of the shops the 'naked' vendor option (only a few shops have them so far), and introduces more food and drinks options.
- Maned wolf
- Howler monkey
- Coatimundi
- Spider monkey
- Ocelot
- Pudu
- Armadillo
- + Emerald tree boa
Winter 2023: Highlands DLC
And a pack with some love for highland animals! Another animal pack this time. And haha, it's uh... basically lots of sheep and goats lol, plus a bear, a cat, and a rodent.
Free update allows players to develop their own scenarios and share them with other players.
- Takin
- Spectacled bear
- Pallas cat
- Markhor
- Alpine marmot
- Chamois
- Japanese serow
- Bighorn sheep
I've got tons of ideas, this is just a grasp. Maybe not my best ideas lol, but enjoy them all the same.