Earthshape

Earthbend 3. Then each creature you control with power less than or equal to that land's power gains hexproof and indestructible until end of turn. You gain hexproof until end of turn.

Appa, the Vigilant

Flying, vigilance
Whenever Appa or another Ally you control enters, creatures you control get +1/+1 and gain flying and vigilance until end of turn.

Katara's Reversal

Counter up to four target spells and/or abilities.
Untap up to four target artifacts and/or creatures.

Sokka's Charge

During your turn, Allies you control have double strike and lifelink.

Fire Nation Turret

At the beginning of combat on your turn, up to one target creature gets +2/+0 and gains firebending 2 until end of turn.
{R}: Put a charge counter on this artifact.
Remove fifty charge counters from this artifact: It deals 50 damage to any target.

Swampbenders

Swampbenders's power and toughness are each equal to the number of Swamps on the battlefield.
Lands you control are Swamps in addition to their other types.