Hold on. Since the site's not down with redundancies, I'm just going to set up a list of what we already have.

Western:
Aries: Indigoat/Imprex are present, but there's room for a sheep.
Taurus: Veemooth/Bovitaur are present. I can't think of another theme.
Gemini: No obvious duality theme in one pixpet. I still like the turtle idea.
Cancer: No crustaceans spotted.
Leo: Feliphene/Kyagrowl are present, room for other felines.
Virgo: I got nothing.
Libra: Primary theme is balance, if that helps.
Scorpio: There's got to be some way of stylizing a scorpion out of the "screaming mimis" zone.
Sagittarius: Porcupine or horse, that is the question. I like porcupine better.
Aquarius: Honeypot ant, see Scorpio notes.
Pisces: We don't have anything straight up aquatic, but I personally would accept frilly salamanders.
Ophiuchus?: We have snakes already, but there could be more.

Chinese:
Rat: No murids.
Ox: Veemooth/Bovitaur.
Tiger: Feliphene line is striped, but not orange.
Rabbit: We have Shluppbun already, but consider jackalopes.
Dragon: Noo-Long
Snake: There's room for more snakes, like I said. Maybe a ball python?
Horse: None present.
Goat/Sheep: We have goats, but nothing fluffy.
Monkey: None present.
Rooster: No Galliformes present.
Dog: Canisqua/Luputrix are present, but there's still room.
Pig: Not present.
(Cat): There's room for small cats, for sure.