Hundred-Handed One

Vigilance
{3}{W}{W}{W}: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)
As long as Hundred-Handed One is monstrous, it has reach and can block an additional ninety-nine creatures each combat.

Ondu Giant

When Ondu Giant enters the battlefield, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Earthshaker Giant

Trample
When Earthshaker Giant enters the battlefield, other creatures you control get +3/+3 and gain trample until end of turn.

Brion Stoutarm

Lifelink
{R}, {T}, Sacrifice another creature: Brion Stoutarm deals damage equal to the sacrificed creature's power to target player or planeswalker.

Fertile Footsteps

Search your library for a basic land card, put it onto the battlefield, then shuffle. (Then exile this card. You may cast the creature later from exile.)

Beanstalk Giant

Beanstalk Giant's power and toughness are each equal to the number of lands you control.

Beanstalk Giant // Fertile Footsteps

Thundercloud Shaman

When Thundercloud Shaman enters the battlefield, it deals damage equal to the number of Giants you control to each non-Giant creature.

Surtland Flinger

Whenever Surtland Flinger attacks, you may sacrifice another creature. When you do, Surtland Flinger deals damage equal to the sacrificed creature's power to any target. If the sacrificed creature was a Giant, Surtland Flinger deals twice that much damage instead.

Borderland Behemoth

Trample
Borderland Behemoth gets +4/+4 for each other Giant you control.

Oathsworn Giant

Vigilance
Other creatures you control get +0/+2 and have vigilance.

Sunrise Sovereign

Other Giant creatures you control get +2/+2 and have trample.

Giant Harbinger

When Giant Harbinger enters the battlefield, you may search your library for a Giant card, reveal it, then shuffle and put that card on top.

Sunder Shaman

Sunder Shaman can't be blocked by more than one creature.
Whenever Sunder Shaman deals combat damage to a player, destroy target artifact or enchantment that player controls.

Basalt Ravager

When Basalt Ravager enters the battlefield, it deals X damage to any target, where X is the greatest number of creatures you control that have a creature type in common.