Half-Giant Traits:

Ability Score Increase:Your Strength and Constitution scores each increase by 1.

Age: Half-giants age slightly slower than humans, reaching adulthood at around age 20. They tend to live a decent bit longer than humans as well, usually living to be no older than 200.

Alignment: Half-giants don't tend toward any alignment in particular.

Size: The smallest half-giant is larger than all but the largest of humans. Your size is Large.

Speed: You have a base walking speed of 30 feet.

Athletic: You have proficiency with the Athletics skill.

Giantkin: Your creature type is considered to be both Giant and Humanoid.

Stone Toss: When you make a ranged attack with an improvised weapon made of stone, you are considered proficient with that improvised weapon, and its damage die increases to 1d6.

Languages: You speak, read, and write Common and Giant.

Subrace: One of your parents was a cloud giant, fire giant, frost giant, hill giant, stone giant or storm giant. Choose one of these subraces.

Cloud Giant

Ability Score Increase. Your Charisma score increases by 1.
Keen Senses. You have proficiency with the Perception skill.
Cloud Giant Magic. You know the gust cantrip and can cast it at will. Starting from 3rd level, you know the spell feather fall and can cast it once. Starting from 5th level, you know the spell fog cloud and can cast it once as a 2nd-level spell. You regain expended uses of this trait when you complete a long rest. Charisma is your spellcasting ability for these spells.

Fire Giant

Ability Score Increase. Your Constitution score increases by 1.
Fireborn. You have resistance to fire damage. Additionally, when you score a critical hit with a melee weapon attack, your weapon ignites in flame and you can roll one of the weapon’s damage dice one additional time and add it to the extra damage of the critical hit. This extra damage is fire damage regardless of the weapon damage type.
Metalworker. You have proficiency with smith's tools.

Frost Giant

Ability Score Increase. Your Wisdom score increases by 1.
Frostborn. You have resistance to cold damage. Additionally, you know the frostbite cantrip and can cast it at will. Starting from 3rd level, you know the spell ice knife and can cast it once, regaining the ability to cast it when you complete a long rest. Wisdom is your spellcasting ability for these spells.
Glacial Native. While you are traveling through arctic terrain, you add twice your proficiency bonus to Intelligence (Nature) and Wisdom (Perception and Survival) checks related to your immediate surroundings, instead of any proficiency bonus that you would normally apply. Additionally, you ignore difficult terrain while in arctic terrain.

Hill Giant

Ability Score Increase. Your Strength score increases by 1.
Barrel Through. When you move, you can attempt to enter the space of a creature that is at least one size smaller than you. When you do so, that creature must succeed on a Strength saving throw or be knocked prone as you enter their space. The DC for this saving throw equals 8 + your Strength modifier + your proficiency bonus. You can't force a creature to make this saving throw more than once per turn.
Thick-Skinned. While you are not wearing armor, your Armor Class equals 10 + your Constitution modifier.

Stone Giant

Ability Score Increase. Your Dexterity score increases by 1.
Darkvision. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.
Stone's Endurance. You can focus yourself to occasionally shrug off injury. When you take damage, you can use your reaction to roll a d12. Add your Constitution modifier to the number rolled, and reduce the damage by that total. After you use this trait, you can’t use it again until you finish a short or long rest.
Stone Camouflage. When you make a Dexterity (Stealth) check to hide in rocky terrain, you are considered proficient in the Stealth skill if you aren't already, and add double your proficiency bonus to the roll, instead of any proficiency bonus you would normally apply.

Storm Giant

Ability Score Increase. Your Intelligence score increases by 1.
Storm Resistance. You have resistance to lightning and thunder damage.
Storm Bolt. You can generate a bolt of lightning in your hand, which you can use to make attacks in combat. This is a ranged spell attack that you can use with the Attack action. The attack has a range of 60 feet, an attack bonus equal to your Intelligence modifier + your proficiency bonus, and deals lightning damage on a hit equal to 1d6 + your Intelligence modifier.