Let's start with the basics, the Olympians.(I will put more than 12 because the Greeks can't decide who in the 12).
For the beginning let's do The Big Three Zeus: God of thunder and lightning, is king of the gods. Poseidon: God of the sea, has an underwater kingdom. Hades: God of death, has an underground kingdom and controls the Underworld.
Now to do the others. Hera: Goddess of marriage, queen of the gods. Apollo: God of music, medicine and prophecies, is an expert archer. Also is brother to Artemis Artemis: Goddess of the hunt, is an expert archer and older sister to Apollo.
Athena: Goddess of wisdom, sprung out of Zeus's forehead. Ares: God of war, first child of Zeus and Hera. Demeter: Goddess of seasons, has a daughter with Zeus. Aphrodite: Goddess of love, is a wife to Hephaestus but loves Ares.
Dionysus: God of wine and grapes, can make anybody drunk. Hermes: God of trade, luck, thieves and travel, is very mischievous. Hephaestus: God of fire, volcanoes and crafting, was thrown off Mount Olympus.
Hestia: Goddess of hearth and home, is the flame tender of Olympus.
Thanks for reading!! I hope you enjoyed! Stay safe!