msem-instigator

When this creature enters, you may exile target non-Cat creature you control. Return that card to the battlefield under its owner's control at the beginning of the next end step.
Arise {3}{W} ({3}{W}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

When Ralezza, Weaver of Okthuros enters, you may put target Aura card that could enchant it from a graveyard onto the battlefield attached to Ralezza.
{1}{W}, Sacrifice an Aura: Ralezza gains indestructible until end of turn.

When Red-Crowned Admiral enters, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Each creature you control with a +1/+1 counter on it has flying.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever a +1/+1 counter is put on Sejiri Skyhunter, it gains flying until end of turn.

First strike
Whenever Silverblade Cathar and at least two other creatures attack, draw a card.

At the beginning of each end step, if you gained life this turn, you get a glory counter. (You lose glory counters before life. A player with ten or more glory counters wins the game.)

Flying
Whenever Skyflock Warrior or another creature you control with flying attacks, create a 1/1 white Bird creature token with flying.

Flying
Whenever Skyline Climber attacks, another target creature you control gains flying until end of turn.

Survivors you control have flying.

Vigilance
When Spear of the Folded Fan enters, if you control a legendary creature, you gain 4 life.

When Strength of the Patient enters, if it was revived, put four +1/+1 counters on it.
Revive {4}{W}{W}{W} ({4}{W}{W}{W}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Flash
When Swift Savior enters, if you control a legendary creature, you may have Swift Savior deal 2 damage to target attacking or blocking creature.

First strike
Art of war — At the beginning of your end step, if Teikoku Cavalry dealt damage to an opponent this turn, put a +1/+1 counter on it.

Creature tokens you control get +1/+1.
Whenever Thyra, Winter's Warden enters or attacks, you may pay {1}{G/W}. If you do, create Bruga, a legendary 2/2 green and white Wolf creature token.

{4}{W}{W}: Create a 4/4 white Angel creature token with flying.
{2}{W}{W}: Populate. (Create a token that's a copy of a creature token you control.)

Double strike
Whenever an Equipment you control enters, create a 3/3 white Archon creature token with flying and attach that Equipment to that token.

Other Rebel creatures you control get +0/+1.
When Veteran Renegade enters, create a 1/1 white Rebel creature token.

Adorned — Visserine's Royal Guard has lifelink as long as it's equipped and/or enchanted.

Flying
Whenever another creature you control enters, you may have Waxing Celestial get +1/+1 until end of turn.

When Wayfaring Swindler enters, destroy all permanents attached to target creature.

Lifelink
Spells your opponents cast cost an additional {1} to cast for each spell they've cast before it this turn.

When Adept Electromancer enters, scry 2, then reveal the top card of your library. If it's an instant or sorcery card, put it into your hand.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Flying
As long as there are five or more different creature types among creatures you control, Adventuring Guildmage gets +1/+0 and has hexproof.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
When Arbiter of Shal'Iv enters, adjudicate. (Create a white enchantment Aura token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)