Juggernaut

Juggernaut attacks each combat if able.
Juggernaut can't be blocked by Walls.

Island

Witch's Vengeance

Creatures of the creature type of your choice get -3/-3 until end of turn.

Chaos Charm

Choose one —
• Destroy target Wall.
• Chaos Charm deals 1 damage to target creature.
• Target creature gains haste until end of turn.

Tunnel

Destroy target Wall. It can't be regenerated.

Goblin Digging Team

{T}, Sacrifice Goblin Digging Team: Destroy target Wall.

Graaz, Unstoppable Juggernaut

Juggernauts you control attack each combat if able.
Juggernauts you control can't be blocked by Walls.
Other creatures you control have base power and toughness 5/3 and are Juggernauts in addition to their other creature types.

Mountain

Siege Dragon

Flying
When Siege Dragon enters the battlefield, destroy all Walls your opponents control.
Whenever Siege Dragon attacks, if defending player controls no Walls, it deals 2 damage to each creature without flying that player controls.

Marble Priest

All Walls able to block Marble Priest do so.
Prevent all combat damage that would be dealt to Marble Priest by Walls.

Deep Freeze

Enchant creature
Enchanted creature has base power and toughness 0/4, has defender, loses all other abilities, and is a blue Wall in addition to its other colors and types.

Swamp

Battering Ram

At the beginning of combat on your turn, Battering Ram gains banding until end of combat. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's blocking.)
Whenever Battering Ram becomes blocked by a Wall, destroy that Wall at end of combat.

Engineered Plague

As Engineered Plague enters the battlefield, choose a creature type.
All creatures of the chosen type get -1/-1.

Mistform Mask

Enchant creature
{1}: Enchanted creature becomes the creature type of your choice until end of turn.