Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is this creature's power.

Rumor Gatherer

Alliance — Whenever another creature you control enters, scry 1. If this is the second time this ability has resolved this turn, draw a card instead.

Guardian Sunmare

Ward {2}
Whenever this creature attacks while saddled, search your library for a nonland permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.
Saddle 4

Appa, Steadfast Guardian

Flash
Flying
When Appa enters, airbend any number of other target nonland permanents you control. (Exile them. While each one is exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever you cast a spell from exile, create a 1/1 white Ally creature token.

Jet, Rebel Leader

Whenever Jet attacks, look at the top five cards of your library. You may put a creature card with mana value 3 or less from among them onto the battlefield tapped and attacking. Put the rest on the bottom of your library in a random order.

Appa, the Vigilant

Flying, vigilance
Whenever Appa or another Ally you control enters, creatures you control get +1/+1 and gain flying and vigilance until end of turn.

Guardian of Faith

Flash
Vigilance
When this creature enters, any number of other target creatures you control phase out. (Treat them and anything attached to them as though they don't exist until their controller's next turn.)

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Armored Skyhunter

Flying
Whenever this creature attacks, look at the top six cards of your library. You may put an Aura or Equipment card from among them onto the battlefield. If an Equipment is put onto the battlefield this way, you may attach it to a creature you control. Put the rest of those cards on the bottom of your library in a random order.

Beza, the Bounding Spring

When Beza enters, create a Treasure token if an opponent controls more lands than you. You gain 4 life if an opponent has more life than you. Create two 1/1 blue Fish creature tokens if an opponent controls more creatures than you. Draw a card if an opponent has more cards in hand than you.

Avatar's Wrath

Choose up to one target creature, then airbend all other creatures. (Exile them. While each one is exiled, its owner may cast it for {2} rather than its mana cost.)
Until your next turn, your opponents can't cast spells from anywhere other than their hand.
Exile Avatar's Wrath.

Firja's Retribution

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create a 4/4 white Angel Warrior creature token with flying and vigilance.
II — Until end of turn, Angels you control gain "{T}: Destroy target creature with power less than this creature's power."
III — Angels you control gain double strike until end of turn.

Appa, Aang's Companion

Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Appa attacks, another target attacking creature without flying gains flying until end of turn.

Guardian Scalelord

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following abilities until end of turn.)
Flying
Whenever this creature attacks, return target nonland permanent card with mana value X or less from your graveyard to the battlefield, where X is this creature's power.

Monk Gyatso

Whenever another creature you control becomes the target of a spell or ability, you may airbend that creature. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)

Secret Rendezvous

You and target opponent each draw three cards.

Reprieve

Return target spell to its owner's hand.
Draw a card.

Serra's Blessing

Creatures you control have vigilance. (Attacking doesn't cause them to tap.)

Alms Collector

Flash
If an opponent would draw two or more cards, instead you and that player each draw a card.

Appa, Loyal Sky Bison

Flying
Whenever Appa enters or attacks, choose one —
• Target creature you control gains flying until end of turn.
• Airbend another target nonland permanent you control. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)

Guardian of the Gateless

Flying
This creature can block any number of creatures.
Whenever this creature blocks, it gets +1/+1 until end of turn for each creature it's blocking.

Guardian Zendikon

Enchant land
Enchanted land is a 2/6 white Wall creature with defender. It's still a land.
When enchanted land dies, return that card to its owner's hand.

Serra's Guardian

Flying (This creature can't be blocked except by creatures with flying or reach.)
Vigilance (Attacking doesn't cause this creature to tap.)
Other creatures you control have vigilance.

Guardian of New Benalia

Enlist (As this creature attacks, you may tap a nonattacking creature you control without summoning sickness. When you do, add its power to this creature's until end of turn.)
Whenever this creature enlists a creature, scry 2.
Discard a card: This creature gains indestructible until end of turn. Tap it.

Bygone Bishop

Flying
Whenever you cast a creature spell with mana value 3 or less, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Dismantling Wave

For each opponent, destroy up to one target artifact or enchantment that player controls.
Cycling {6}{W}{W} ({6}{W}{W}, Discard this card: Draw a card.)
When you cycle this card, destroy all artifacts and enchantments.

Scout's Warning

The next creature card you play this turn can be played as though it had flash.
Draw a card.

Dawn of Hope

Whenever you gain life, you may pay {2}. If you do, draw a card.
{3}{W}: Create a 1/1 white Soldier creature token with lifelink.

Guardian of Ghirapur

Flying
When this creature enters, exile up to one other target creature or artifact you control. Return it to the battlefield under its owner's control at the beginning of the next end step.

Guardians' Pledge

White creatures you control get +2/+2 until end of turn.

Serra's Embrace

Enchant creature
Enchanted creature gets +2/+2 and has flying and vigilance. (Attacking doesn't cause it to tap.)

Teleportation Circle

At the beginning of your end step, exile up to one target artifact or creature you control, then return that card to the battlefield under its owner's control.

Bronze Guardian

Double strike
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Other artifacts you control have ward {2}.
Bronze Guardian's power is equal to the number of artifacts you control.

White Lotus Tile

This artifact enters tapped.
{T}: Add X mana of any one color, where X is the greatest number of creatures you control that have a creature type in common.

Wall of Omens

Defender
When this creature enters, draw a card.

Halo Fountain

{W}, {T}, Untap a tapped creature you control: Create a 1/1 green and white Citizen creature token.
{W}{W}, {T}, Untap two tapped creatures you control: Draw a card.
{W}{W}{W}{W}{W}, {T}, Untap fifteen tapped creatures you control: You win the game.