Angel- A spiritual being who serves God.
Banshee- Female Irish fairy who wails to warn impending death.
Basilisk- King of the serpents.
Centaur- Half man, half horse.
Cyclops- Giant with a single eye in the middle of the forehead.
Demon- supernatural evil spirit.
Djinni (genie)- evil or good spirit that grants wishes.
Doppleganger- human double.
Dragon- large flying reptile, sometimes fire-breathing.
Elemental- a being composed of one of the fundamental elements.
Fae- umbrella term for other-worldly little people.
Gargoyle- hideous creatures carved on Gothic buildings as water spouts and to ward off evil spirits.
Ghost- disembodied spirit.
Ghoul- evil spirit that feeds on corpses.
Giant- humaniod creature of prodigious size and strength.
Gremlin- mechanically oriented mischievous creature.
Griffin- Lion's body, eagle's head, long ears and an eagle's claws.
More to come. Some of these creatures (those that I haven't already) will be described more in later posts.