Heracles
Zeus
Harpy
Centaur
first two feel like locks.
last two i'm unsure of. Cerberus is very frequently used for a guard beast, hound of hell, etc but the Harpy is being slept on; those half bird half woman creatures are used in regular language to this day, they're with countless variations in just about every action game and a bunch of RPGs. out of all the monsters i think they're the #1 for greek myth, even more so than Cerberus or Centaurs, who i'd say are #2, largely because i don't give sirens the credit for mermaids.
"Maybe it's a tentacle, molesting the planet itself. - Aschen Brodel.