Chimera
Mixture of beasts, lion, goat, dragon or some such
Scylla
Don't know
Oni
no idea
Gorgon
Actually people usually think this refers to the Medusa but it also refers to any of the cursed titans punished by the Gods.
Kappa
Greek letter?
Hydra
Nine headed?(IIRC) land bound dragon.
Cyclops
One eyed giant with a foul temper and a like of strong drink, not bright.
Mermen
opposite of mermaids
Minotaur
The beast in the Labaryinth of minos, a large powerfully strong man with the head of a bull.
Basilisk
A lizard creature capable of paralysing all who gaze upon it.
Djinn
Think the Gennie of the lamp, creatures of fire that live in the desert and are usually invisible, they can sometimes be seen as dust devils.
Golem
Creature made up of many different materials although most commonly stone, very tough and extremely resistant to many forms of damage and as mindless automatons controlled often by a powerfull mage, they are unaffected by most magic.
Gryphon
Large Eagle like creature. Easilly capable of carrying several humanoids
Hippocampus
I forget
Hippogryph
Mix of a horse and a gryphon
Lamia
It'll come to me
Lycanthrope
Were animal, most commonly a wolf
Pegasus
Duh, Winged Horse
Phoenix
Everyone knows what a pheonix is a bird that can return from the ashes of the flames to life
Rukh
Also known as a castle, best to keep these for castelling opportunities later
Banshee
Originally called the Bean Sidhe pronounced Ban shee this wicked Godess often appears when someone is to die her cry is said to turn men insane. Typically though just the herald of doom
Familiar
Follower of a mage, dependant on his moral compass, it could be an evil imp or a sage owl
Naga
Snake like creatures, vaguely remember these guys I think?
Teng
Don't know.
Radioactive Monkey!
No one has ever been able to document these creatures, they seem to change with the seasons having all sorts of probably mythical powers assigned to them? Your guess is as good as mine?
Off the top of my head, I guess I could actually look them up in the monstrous manual(I knew there was a reason I kept that book

) But you could just type there names into google.