Amphibian - Members of this class are capable of breathing gaseous atmosphere as well as a liquid one via two methods of respiration, lungs and gills.  Most amphibians require moist environments in which to live healthily.

Avian - This class signifies beings that are capable of flight in normal gaseous atmospheres.  Typically, avian beings have light feathers to aid them in their flights.

Brain - Brains are typically primarily single-organ organisms with mainly their mental organs, usually naturally from mineral-rich bodies of water.  Some Brain beings have additional organs that act as sensors, defenses, appendages, etc.

Deep Space - The Deep Space class contains widely varied beings that are uniquely able to live naturally in the cold vacuum of space.

Electrical - Members of this class have bodies of electrical energy.  Often these creatures wear static-protective suits when visiting non-native worlds.

Floral - Floral races are intelligent plant-like beings.  Their bodies typically contain strong cellulose and chloroplasts.

Giant Cellular - Beings of this class have bodies consisting of enormous versions of the microscopic cells, where their organs free-float in bodily liquid.

Humanoid - This class of beings typically have two arms and two legs with an upright posture off of a central trunk topped with a head.  Generally, their skin is bare of hair, feathers, etc.

Ichthyoid - Members of this class usually live underwater and breathe through gills.  Usually their bodies are sleek and designed for swimming.

Insectoid - Insectoid beings have exoskeletons, multiple arms and legs, and complex methods of sensing including eyes and antennae. 

Lasidaze - This class contains beings who have bodies constructed primarily of stone-like biological matter.

Liqui - Beings of this class have highly viscious bodies that are nearly liquid in their natural state.

Mammalian - Mammalian beings have accelerated senses, hairy bodies, bare live young, and produce milk.

Nebular - The nebular class signifies beings who naturally live in gaseous nebulae.

Pyror - Beings of the Pyror class have fiery bodies and are typically native to very hot environments.

Raska - This class of beings are very fleshy and typically have blue skin.

Reptilian - Reptilian beings have scale-covered bodies and egg-born young.

Robotic - Robots who have achieved artificial intelligence are placed in the Robotic class.

Space Amphibian - Members of this class are capable of breathing atmosphere as well as existing in the vacuum of space.

Spore - Beings from this clas reproduce via spores that are spread from their bodies.

Yari - The Yari class holds three related races that have chloroplast, three arms, live young, and scale-like fur.