Doom Reigns Supreme

Whenever a Villain you control enters, each opponent loses 1 life and you gain 1 life. Put a plan counter on this enchantment.
When the fifth plan counter is put on this enchantment, sacrifice it. When you do, target opponent exiles the top five cards of their library. You may cast up to two spells from among the exiled cards without paying their mana costs.

Airbending Lesson

Airbend target nonland permanent. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Draw a card.

Heartless Act

Choose one —
• Destroy target creature with no counters on it.
• Remove up to three counters from target creature.

Plains

Strategic Betrayal

Target opponent exiles a creature they control and their graveyard.

Airbender Ascension

When this enchantment enters, airbend up to one target creature.
Whenever a creature you control enters, put a quest counter on this enchantment.
At the beginning of your end step, if this enchantment has four or more quest counters on it, exile up to one target creature you control, then return it to the battlefield under its owner's control.

Obsessive Pursuit

When this enchantment enters and at the beginning of your upkeep, you lose 1 life and create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you attack, put X +1/+1 counters on target attacking creature, where X is the number of permanents you've sacrificed this turn. If X is three or greater, that creature gains lifelink until end of turn.

Starry-Eyed Skyrider

Flying
Whenever this creature attacks, another target creature you control gains flying until end of turn.
Attacking tokens you control have flying.

Abandoned Air Temple

This land enters tapped unless you control a basic land.
{T}: Add {W}.
{3}{W}, {T}: Put a +1/+1 counter on each creature you control.

Swamp

Hardened Tactician

Sunpearl Kirin

Flash
Flying
When this creature enters, return up to one other target nonland permanent you control to its owner's hand. If it was a token, draw a card.

Voice of Victory

Mobilize 2 (Whenever this creature attacks, create two tapped and attacking 1/1 red Warrior creature tokens. Sacrifice them at the beginning of the next end step.)
Your opponents can't cast spells during your turn.

The Sibsig Ceremony

Creature spells you cast cost {2} less to cast.
Whenever a creature you control enters, if you cast it, destroy that creature, then create a 2/2 black Zombie Druid creature token.

Doctor Doom

When Doctor Doom enters, create two 3/3 colorless Robot Villain artifact creature tokens named Doombot.
As long as you control an artifact creature or a Plan, Doctor Doom has indestructible.
At the beginning of your end step, you draw a card and lose 1 life.

Godless Shrine

({T}: Add {W} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.