MAGGOT – small and cheap creature, good for combining with big ones (abilities included: overpopulation, colony, regeneration, immunity)
LEATHERBACK SEA TURTLE – bigger and slower than snapping turtle, defence as high
THOMPSON GAZELLE – smaller but similar to zebra, horns
DRACO LIZARD – range attacking creature with hovering ability
SIAMESE FIGHTING FISH – very strong size 1 water unit
FIDDLER CRAB – looks cool, pain in the arse for developers because it's dissymmetrical
ALLIGATOR - smaller and faster than a crocodille
GEJIGEJI CENTIPEDE - just because
ANTLION - size 1, high-defenced, barrier destroyer
SCORPION FLY - I think the name speaks for itselfHAWK - smaller and weaker than eagle