org.bukkit.entity
Interfaces 
Ageable
Ambient
Animals
AnimalTamer
Arrow
Bat
Blaze
Boat
CaveSpider
Chicken
ComplexEntityPart
ComplexLivingEntity
Cow
Creature
Creeper
Damageable
Egg
EnderCrystal
EnderDragon
EnderDragonPart
Enderman
EnderPearl
EnderSignal
Entity
ExperienceOrb
Explosive
FallingBlock
FallingSand
Fireball
Firework
Fish
FishHook
Flying
Ghast
Giant
Golem
Hanging
Horse
HumanEntity
IronGolem
Item
ItemFrame
LargeFireball
LeashHitch
LightningStrike
LivingEntity
MagmaCube
Minecart
Monster
MushroomCow
NPC
Ocelot
Painting
Pig
PigZombie
Player
PoweredMinecart
Projectile
Sheep
Silverfish
Skeleton
Slime
SmallFireball
Snowball
Snowman
Spider
Squid
StorageMinecart
Tameable
ThrownExpBottle
ThrownPotion
TNTPrimed
Vehicle
Villager
WaterMob
Weather
Witch
Wither
WitherSkull
Wolf
Zombie
Enums 
CreatureType
EntityType
Horse.Color
Horse.Style
Horse.Variant
Ocelot.Type
Skeleton.SkeletonType
Villager.Profession