Playing In The Big Leagues
Giants, and giant-like creatures, are fearsome foes. Above and beyond their prodigious strength, their size and mass allows them to perform incredible feats.
Strength ratings are not given for giants. Their massive strength is already figured into hit and increased damage rolls. DMs are encouraged not to double dip.
Send 'em Flying: If a giant succeeds in an unarmed attack against a character, they may knock (kick, shove, or throw) that character away from them.. preferably into something or someone else. At the giant's discretion, the character may travel up to 5 feet for each die of damage the giant is capable of doing, and takes normal damage from the giant's attack.
Sweep: Instead of attacking a single target, a giant may choose to sweep all targets in front of them, with one massive swing. This attack only does half damage, but effects all targets within reach of their weapon. No attack roll is needed, but all targets are allowed a saving throw to escape the attack without taking damage.
Stomp 'em Flat: If the giant so chooses, they may use an unarmed attack to simply knock the character prone, doing full damage, and pin the character underfoot. Unless the character escapes next round, or help arrives, they will be crushed like a bug. A giant may only pin one character underfoot at a time.
Bull Rush: If a giant charges a smaller character, they may perform a free attack on that character, and continue up to their full movement. However, characters so charged, may set any spears or polearms to stop the rush. On a successful attack roll, they do double damage (roll twice the damage dice, any bonuses apply just once) and the giant is stopped from going further.
Now for the characters -
Beware Stinging Gnats: Giants must be mindful of smaller creatures attacking their legs. If characters specifically attack a giant's legs and manage to do 1/3 the giant's hit points in cumulative damage, the giant will no longer be able to perform any of its special attacks.
"Q: Why do giants always throw boulders?
A: because they often engage numerous, smaller humanoids in conflict. Smaller humanoids don't like to be squished, so they stay at range if they can. Giants only carry giant-sized spears and other ranged weapons when expecting to fight other giants, so boulders become their weapons of choice. A giant will typically carry 0 to 5 (1d6-1) throwing rocks in a bag on their hip."