msem-instigator

Flying
Whenever another creature you control enters, create an Idol token.
Whenever you put a +1/+1 counter on Ya'Ling, put a +1/+1 on each other creature you control. This ability triggers only once each turn.

Put up to one target permanent card from your graveyard on top of your library. (Then exile this card. You may play the land later from exile.)

Equipped creature gets +3/+1 and has haste.
Equip Soldier or Warrior {1}
Equip {4}

Spirited (When this enters, you may activate one of its activated abilities without paying its cost.)
{3}, {T}: Create a colorless Equipment artifact token with “Equipped creature gets +1/+1” and equip {1}. Attach that token to a creature you control.

({T}: Add {B} or {R}.)
As Vacated Bar enters, you may pay {1}. If you don't, Vacated Bar enters tapped.

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Heroic — Whenever you cast a spell that targets Aegis Hero, put a +1/+1 counter on Aegis Hero.

Whenever you cast a noncreature spell, if you control exactly one creature, copy that spell. You may choose new targets for the copies. (If it's a permanent, it resolves as a token.)

Colossal 4—{5}{U}{U}{U} (You may cast this for its colossal cost to have it enter with four +1/+1 counters; or pay {5}{U}{U}{U} as a sorcery: Put four +1/+1 counters on it if it has none.)
Whenever Megalokraken enters or attacks, reveal the top X cards of your library, where X is Megalokraken's power. You may cast a noncreature spell with mana value X or less from among them without paying its mana cost. Put the rest on the bottom of your library in a random order.

Enchant creature
Enchanted creature gets +2/+2.
At the beginning of combat on your turn, enchanted creature gains your choice of flying, vigilance, or lifelink until end of turn.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Flying
{2}{W}: Prevent all damage that would be dealt to and dealt by creatures with counters on them this turn.

[+2]: Up to one target creature gains deathtouch until your next upkeep.
[–3]: Target player sacrifices a creature and discards a card.
[–8]: Exile all creature cards from all graveyards, then create an X/X black Horror creature token with indestructible, where X is the total power of creatures exiled this way.

Flash
When Guppyfin Duelist enters, create a green Aura enchantment token named Piranha's Prowess attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2.” Untap that creature.

Return target permanent to its owner's hand.
Coalesce {7}{U} (You may cast this from your graveyard for {7}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
{2}{G}: Crazed Sprareos gets +2/+2 until end of turn. Activate only once each turn.

Foretell {1}{G}{G} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Choose one. If this spell was foretold, you may choose both instead —
• Create two tapped 1/1 white Peasant creature tokens.
• You gain 7 life.

If a player would lose life, that player loses 3 life instead.
If a player would gain life, that player gains 3 life instead.

When Bjarndyr Mender enters, other creatures you control get +1/+1 and gain indestructible until end of turn.

Flying (This creature can't be blocked except by creatures with flying or reach.)
{R}: Newborn Dragon gets +1/+0 until end of turn.

As Foreboding Ruins enters, you may reveal a Swamp or Mountain card from your hand. If you don't, Foreboding Ruins enters tapped.
{T}: Add {B} or {R}.

{2}, {T}: Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step. Activate only as a sorcery.

Destroy target creature. (Cast a copy of this spell once while this creature is on the battlefield.)

Haste
When Greenwood Outrider enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of storied permanents you control. (Enchantments and legendary permanents are storied.)

Draw three cards, then put two cards from your hand on top of your library in any order.

Flying, vigilance
When Manafly enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Target creature gets -2/-1 until end of turn. When it dies this turn, its controller loses 5 life.