Wall of Ice

Glacial Wall

Hover Barrier

Wall of Frost

Defender
Whenever Wall of Frost blocks a creature, that creature doesn't untap during its controller's next untap step.

Arcades, the Strategist

Flying, vigilance
Whenever a creature you control with defender enters, draw a card.
Each creature you control with defender assigns combat damage equal to its toughness rather than its power and can attack as though it didn't have defender.

Axebane Guardian

Defender
{T}: Add X mana in any combination of colors, where X is the number of creatures you control with defender.

Wall of Denial

Defender, flying
Shroud (This creature can't be the target of spells or abilities.)

Tree of Redemption

Defender
{T}: Exchange your life total with Tree of Redemption's toughness.