A lot of them are a lot more than that.
Zeus (Jupiter)- Sky, Thunder, Lightning, and is the king of gods.
Posiden (Neptune)- Ocean, sea, other bodies of water, earthquakes, and horses
Hades (Pluto)- Death, the underworld, wealth, and is the personification of the underworld as well as being the god of it.
Hera (Juno)- Marriage, fertility (there are several fertility goddesses), women, and protector of women and children.
Hestia (Vesta)- The hearth, the flame, and represents peace and domestic life.
Ares (Mars)- War, the spirit of battle.
Hephaestus (Vulcan)- Fire, forges, and blacksmithing.
Athena (Minerva)- Wisdom, war, crafts, weaving, practical thought, and the protectress of cities.
Artemis (Diana)- Hunt, wild animals, the night, the moon, vegetation, childbirth, and chastity.
Apollo (still Apollo to the Romans)- Archery, music, dance, truth, prophecy, healing, diseases, the Sun, light, and poetry.
Dionysus (Bacchus)- Wine, fruitfulness, party, vegetation, and ecstasy.
Demeter (Ceres)- Agriculture and harvest.
Hermes (Mercury)- Shopkeepers, merchants, travelers, transporters of goods, thieves, tricksters, and is the messenger of the gods and one of the very few allowed to enter and exit the underworld without repercussions.
There are hundreds more as well, though they are mostly minor gods/goddesses.
