A giant is a humanoid creature of great strength, usually of at least Large size. Giants have a number of racial Hit Dice and never substitute such Hit Dice for class levels like some humanoids. Giants have low-light vision, and treat Intimidate and Perception as class skills.
Source Pathfinder Campaign Setting: Giants Revisited
Cloud Giant: Diametrically aligned, mountain-dwelling colossi with supernatural powers over the sky and clouds, as well as possible ties to mysterious, mythical cloud cities.
Cyclops: One-eyed, rage-filled giants capable of glimpsing into the near future, yet whose expansive empires have been reduced to little more than rubble and far-flung enclaves.
Fire Giant: Legendary crafters of tremendous weapons and invincible armor, whose lust for war and domination drives them to spread devastation throughout the lands.
Frost Giant: Tribal raiders who make their homes in the frostbitten north, following the whims of merciless jarls and waylaying travelers for sport, plunder, and food.
Hill Giant: Dim-witted, inbred goliaths who aimlessly wander rocky lands, preying on nearby villages and raining boulders down on any who tread too close.
Marsh Giant: Swamp-dwelling, fish-like degenerates who make sacrifices to a foul demon lord, bringing them grotesque powers and dark alliances with horrid sea-spawn.
Rune Giant: Rune-covered, magically crossbred warriors designed for the sole purpose of enslaving all other members of giantkind to build their monstrous monuments.
Stone Giant: Skilled artisans, hunters, and historians capable of communing with the earth and stones to bring them closer to the spiritual ways of their ancient forebears.
Storm Giant: Benevolent but tempestuous seafarers who travel the oceans in hopes of vanquishing evil, spreading the ideals of goodness, and engaging different cultures.
Taiga Giant: Nomadic, crimson-haired tribespeople who dwell in hoarfrost-rimed forests and hunt down any who dare to intrude upon nature and the sacred lands of their people.