Orthrus. A fearsome two-headed hound that lived with giants
Sphinx. A half human, half lion who would slay anybody who did not answer her riddles. When Oedipus was able to answer a riddle correctly, she jumped into the ocean in a fit of rage and drowned.
Nemean Lion. A gigantic lion with impenetrable skin that eventually became the star constellation Leo.
In Greek mythology, Centaurs (or Kentauroi) are half-man, half horse creatures that inhabited the mountains and forests of Thessaly.