Counterspell

Shield-Wall Sentinel

Defender
When Shield-Wall Sentinel enters, you may search your library for a creature card with defender, reveal it, put it into your hand, then shuffle.

Walking Bulwark

Defender
{2}: Until end of turn, target creature with defender gains haste, can attack as though it didn't have defender, and assigns combat damage equal to its toughness rather than its power. Activate only as a sorcery.

Crashing Drawbridge

Defender
{T}: Creatures you control gain haste until end of turn.

Access Tunnel

{T}: Add {C}.
{3}, {T}: Target creature with power 3 or less can't be blocked this turn.

Wall of Essence

Defender (This creature can't attack.)
Whenever Wall of Essence is dealt combat damage, you gain that much life.

Vine Trellis

Defender (This creature can't attack.)
{T}: Add {G}.

Wall of Mulch

Defender (This creature can't attack.)
{G}, Sacrifice a Wall: Draw a card.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Wall of Denial

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

Wall of Junk

Defender (This creature can't attack.)
When Wall of Junk blocks, return it to its owner's hand at end of combat. (Return it only if it's on the battlefield.)

Stalwart Shield-Bearers

Defender
Other creatures you control with defender get +0/+2.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Tetsuko Umezawa, Fugitive

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

Brokers Hideout

When Brokers Hideout enters, sacrifice it. When you do, search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Resolute Watchdog

Defender
{1}, Sacrifice Resolute Watchdog: Target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Fell the Mighty

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

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Wall of Ice

Wall of Omens

Defender
When Wall of Omens enters, draw a card.

Perimeter Captain

Defender
Whenever a creature you control with defender blocks, you may gain 2 life.

Saruli Caretaker

Defender
{T}, Tap an untapped creature you control: Add one mana of any color.

Wall of Tanglecord

Defender
{G}: Wall of Tanglecord gains reach until end of turn. (It can block creatures with flying.)

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Wall of Tears

Defender (This creature can't attack.)
Whenever Wall of Tears blocks a creature, return that creature to its owner's hand at end of combat.

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 Hope

Defender (This creature can't attack.)
Whenever Wall of Hope is dealt damage, you gain that much life.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Overgrown Battlement

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

Riptide Turtle

Stoneskin

Flash
Enchant creature
Enchanted creature gets +0/+10.

Negate

Suspicious Bookcase

Defender
{3}, {T}: Target creature can't be blocked this turn.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Steel Wall

Cultivate

Dawn

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Return all creature cards with power 2 or less from your graveyard to your hand.

Dusk

Destroy all creatures with power 3 or greater.

Dusk // Dawn

Wall of Stolen Identity

You may have Wall of Stolen Identity enter as a copy of any creature on the battlefield, except it's a Wall in addition to its other types and has defender. When you do, tap the copied creature and it doesn't untap during its controller's untap step for as long as you control Wall of Stolen Identity.

Wall of Frost

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