Whenever a player casts a white spell, you may pay . If you do, you gain 1 life.

Vigilance
Whenever you attack, you create a Food token for each player being attacked.
, , Tap X untapped Foods you control: Create X 1/1 white Human creature tokens.

Flying
Whenever Appa attacks, another target attacking creature without flying gains flying until end of turn.

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.

Flash
Flying
When Appa enters, airbend any number of other target nonland permanents you control.
Whenever you cast a spell from exile, create a 1/1 white Ally creature token.

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.

Convoke
One or two target creatures each get +2/+1 until end of turn.

If this spell was cast from your hand and you've cast another spell named Approach of the Second Sun this game, you win the game. Otherwise, put Approach of the Second Sun into its owner's library seventh from the top and you gain 7 life.

When April O'Neil enters, scry 2.
April O'Neil can't be blocked by creatures with power 3 or greater.

Flying
Bushido 1

Web-slinging
As Arachne enters, look at an opponent's hand, then choose a card type other than creature.
Spells of the chosen type cost more to cast.

Enlist
Whenever a creature you control attacks, if it enlisted a creature this combat, the creature that attacked gains double strike until end of turn. If that creature's power is 4 or greater, draw a card.

Other Cats you control get +1/+1.
Whenever Arahbo or another nontoken Cat you control enters, create a 1/1 white Cat creature token.

When this creature enters, you gain 3 life.

Double strike
Whenever this creature enters or attacks, another target Warrior creature you control gains double strike until end of turn.

When this creature enters, exile up to two target cards from a single graveyard.
, : Tap target creature.

, : This creature deals 3 damage to target attacking or blocking creature. This creature doesn't untap during your next untap step.

Vigilance
When this creature enters, each player's life total becomes the highest life total among all players.

Flying
When this creature enters, target creature gets +1/+1 and gains flying until end of turn.

Equipped creature has flying.
Equip
Equipment swap (: Exchange this Equipment with an Equipment card in your hand. If this Equipment was attached to a creature, attach the new Equipment to that creature.)

, Remove X +1/+1 counters from this creature: It deals X damage to target attacking or blocking creature.
Modular 1

Lifelink
Modular 1

When this artifact enters, search your library for up to two basic Plains cards, reveal them, put them into your hand, then shuffle.
Whenever a land an opponent controls enters, if that player controls more lands than you, you may put a land card from your hand onto the battlefield.

Flying, vigilance

Flash
Flying, vigilance
When Archangel Avacyn enters, creatures you control gain indestructible until end of turn.
When a non-Angel creature you control dies, transform Archangel Avacyn at the beginning of the next upkeep.

Flying
As this creature enters, each player chooses war or peace.
Creatures controlled by players who chose war get +3/+0.
Creatures controlled by players who chose peace get +0/+3.

Flying
Lifelink
Whenever you gain life, put a +1/+1 counter on each creature you control.

Flying
As long as this creature is untapped, creatures can't attack you or planeswalkers you control unless their controller pays for each of those creatures.
As long as this creature is attacking, creatures can't block unless their controller pays for each of those creatures.