Everybody Hates Hades: Hades being cast as a villain in modern works because he was the God of the Dead. In the actual myths he was one of the nicer Gods.
Forged by the Gods: Hephastus, God of the Forge is the Trope Namer. If there's any powerful weapons or master craftworking in a myth, 9 times out of 10 it was made by him.
Don't Look Back: Orpheus went to The Underworld to get his wife after she died. Hades, Lord of the Underworld told him that he could take his wife so long as he didn't look back before getting out of the Underworld. He did right before leaving.
The Hecate Sisters: The Maiden, the mother, and the crone. Named for the Goddess.
Show of Theseus: Named for the actually serious philosophical paradox of the Ship of Theseus, which asks whether a vessel replaced plank by plank is still the same boat.
Woman Scorned: Medea is the Trope Namer. She sacrificed a lot for Jason because she loved him. Then he ditched her. That was a bad idea.
Illiad
Achilles Heel: Named for Achilles' heel. In the story of Achilles, his mother made him Nigh Invulnerable in every part of the body except for his heel. Didn't end well for him.
Achilles in His Tent: Another one named by Achilles. Achilles' Beautiful Slave Girl Briseis was taken away from him by Agammemnon, so in anger he chose not fight for the Greeks. Considering the fact that he was their ace it really screwed them over.
Cassandra Truth: Cassandra was a princess of Troy who could read the future, but was cursed to never be believed.
Launcher of a Thousand Ships: Helen of Troy is the Trope Namer. So beautiful that almost every prince in Greece wanted to marry her. Her father, who was afraid of upsetting them, was advised by Odysseus, to make them take an oath that they'd protect her should anything happen to her. Then Paris came along and eloped with her. And suddenly a 1000 Greek ships were setting off for Troy.
The Cassandra: Someone who is not believed, even though they speak the truth.
Trojan Horse: A tactic, where a group or person pretends to give up and offers a gift. They hide in that gift, in order to pass their enemies defenses and catch them off guard.