Wall of Frost

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

Wall of Mist

Tetsuko Umezawa, Fugitive

Creatures you control with power or toughness 1 or less can't be blocked.

Overgrown Battlement

Defender
{T}: Add {G} for each creature you control with defender.

Slaughter the Strong

Each player chooses any number of creatures they control with total power 4 or less, then sacrifices all other creatures they control.

Wall of Blossoms

Defender
When Wall of Blossoms enters, draw a card.

Tower Defense

Creatures you control get +0/+5 and gain reach until end of turn.

Angelic Wall

Defender (This creature can't attack.)
Flying

Wall of Glare

Defender (This creature can't attack.)
Wall of Glare can block any number of creatures.

High Alert

Each creature you control assigns combat damage equal to its toughness rather than its power.
Creatures you control can attack as though they didn't have defender.
{2}{W}{U}: Untap target creature.

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.

Wall of Denial

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

Wall of Runes

Defender (This creature can't attack.)
When Wall of Runes enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Fell the Mighty

Destroy all creatures with power greater than target creature's power.

Axebane Guardian

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