The vet idea from lucycatx is a brilliant idea id like to have my sims work as a vet/volunteer. what id like to see is
1.Raven-canary-parrot (large/small) to sleep in cage or aviary were you need to clean feed etc not just look at them and think Ooo pretty. They need to be wild until you train them unless you purchase a tamed bird. They can live caged at bedtime and have a bird stand through the day in various types of stands pole with T bar or branches etc with toys available for them to play with.
2. Hedgehogs available to live indoor/out but would be better to be available if you lived in towns so they could have a garden to run around in.
3.Cats, with toys being able to breed if wanted. available in many colours and various types of pets with various coloured eyes.
4. Dogs again various types/colours/long-short haired small-medium-large. Pulling owners along until they learn to walk on the lead correctly or walk beside you without lead once trained. There are so many breeds available but as a few suggestions off the top of my head would be, Mutt - german shepherd- doberman- eurasier - english setter - great dane - mastiff.
5. Lizard
Snake
Rat
Spider ( could have scared of spider trait that makes sim scream/cower if seen one running around and teen letting it run round as mischief trait)
Bee keeper (makes honey to sell in market and use in recipes)
Stick insects for child