Wall of Frost

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

Keening Stone

{5}, {T}: Target player mills X cards, where X is the number of cards in that player's graveyard.

Wall of Blossoms

Defender
When Wall of Blossoms enters, draw a card.

Overgrown Battlement

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

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Rolling Thunder

Rolling Thunder deals X damage divided as you choose among any number of targets.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Axebane Guardian

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

Colossus of Akros

Defender, indestructible
{10}: Monstrosity 10. (If this creature isn't monstrous, put ten +1/+1 counters on it and it becomes monstrous.)
As long as Colossus of Akros is monstrous, it has trample and can attack as though it didn't have defender.