Positive words:
Kitten, cat, bird used for cute females. Filly (young female horse) is one that's used in Southern US, but it sounds strange to people outside there.
Puppy - babies and infants (boys)
Bear, horse, lion used to talk about men who are strong or big/tall
Negative words:
Pig- disgusting, not clean, lazy (both genders)
Snake, weasel, rat - tricky people, liars (both genders)
Cow- fat or stupid (women)
Whale- fat (women)
Dog- gross or rude (men)
Moose - very tall people (both genders. but this can be said nicely among friends)