http://mason.gmu.edu/~oarans/orest.html

               Here is a list I found in the link and I think it’s very useful. The link talks about the background of Electra. It’s not focus on it but it’s about the house of Pelops. It answered many of my questions of where the characters f Electra came from.

AEGISTHUS - He avenged his family through the love of the enemy's wife.

AGAMEMNON - Military commander of all Greeks.

APOLLO - God who loved Cassandra in vain.

ARTEMIS - Goddess, sister of Apollo, demanding the sacrifice of the king's daughter.

ATHENA - Goddess who found a mutually acceptable solution.

ATREUS - He cooked cannibalistic dinner for his brother.

CASSANDRA - Captive princess, prophetic virgin.

CLYTEMNESTRA - She killed her victorious husband.

DELPHI - Central oracle of the world.

ELECTRA - She helped her brother to kill their mother.

ERINNYES (Furies) - They chased Orestes around the world.

EUMENIDES - Euphemistic name of the spirits of vengeance.

HELEN  - Her face lauched the thousand ships.

IPHIGENIA - She was sacrificed on the goddess' altar.

MYCENAE - City of Agamemnon.

ORESTES - He killed his mother and thus avenged his father.

PELOPS - He won his bride by chariot-race.

PYLADES - He followed his matricide friend on the mission.

TANTALUS - He cooked his son, Pelops, for the party of the gods. Tantalus was punished in the underworld by eternal thirst and hunger in view of drink and food: hence "tantalize."

THYESTES - He ate his children for dinner.

TROY - City destroyed by Agamemnon.