Vent Sentinel

Defender
{1}{R}, {T}: Vent Sentinel deals damage to target player or planeswalker equal to the number of creatures you control with defender.

Doorkeeper

Defender
{2}{U}, {T}: Target player mills X cards, where X is the number of creatures you control with defender.

This land enters tapped.
{T}: Add {U} or {B}.

Gateway Plaza enters tapped.
When Gateway Plaza enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Highland Lake enters tapped.
{T}: Add {U} or {R}.

Defender (This creature can't attack.)
{R}: Wall of Fire gets +1/+0 until end of turn.

Defender
Sacrifice another creature: Corpse Blockade gains deathtouch until end of turn.

Defender
{3}{B}, {T}: Target opponent loses 2 life, then reveals a card at random from their hand.

Defender
{T}: Target creature gains haste until end of turn.

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {R}.

Defender
Aetherflame Wall can block creatures with shadow as though they didn't have shadow.
{R}: Aetherflame Wall gets +1/+0 until end of turn.