msem-instigator

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Ulek Windrider envisions an instant or sorcery card, it gets +1/+0 and gains flying until end of turn.

Tribute 1 (As this creature enters, an opponent of your choice may put a +1/+1 counter on it.)
When Lasis Persecutor enters, if tribute wasn't paid, it gains deathtouch. (This effect lasts indefinitely.)

Equipped creature gets +2/+1.
Whenever equipped creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability.
Equip {2}

When Keepsake of Binding enters, exile target creature an opponent controls until Keepsake of Binding leaves the battlefield.
{4}, {T}: Tap target creature with power less than the exiled card's power.

({T}: Add {W} or {B}.)
Dreary Township enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

This spell costs {1} less to cast for each card put into your graveyard from anywhere this turn.
At the beginning of each player's upkeep, that player loses 1 life, discards a card, and sacrifices a creature.

Flying
Whenever Yawning Crane deals combat damage to an opponent, target tapped creature that player controls doesn't untap during its controller's next untap step.

Artifact spells you cast cost {1} less to cast.
The first ability of an artifact you activate each turn costs {1} less.

Choose one —
• You gain hexproof until end of turn.
• Target creature you control gains double strike until end of turn.
• Exile target card from a graveyard. You gain 4 life.

When Liturgy of Brine enters, draw a card, then you may put a land card from your hand onto the battlefield tapped.
Invocation — Whenever you spend four or more mana to cast a spell or activate an ability during your turn, Liturgy of Brine becomes a 5/5 Kraken Horror creature in addition to its other types until end of turn.

Flash
Flying
When Spectrum Archmage enters, return target spell to its owner's hand, then abound. (To abound, you may cast a spell that costs less than this from your hand without paying its mana cost.)

Wander {2}{W}{W} (You may cast this from the battlefield for its wander cost.)
[–1]: Create a 1/1 white Bird creature token with flying or a 2/2 black Cat creature token.
[–2]: If a permanent entering the battlefield under your control this turn causes an ability of a permanent you control to trigger, that ability triggers an additional time.
[–3]: Put a +1/+1 counter on each creature you control.

Protection from instants and from sorceries
When Warbringer Titan enters or attacks, create two 1/1 white Soldier creature tokens with melee. (Whenever that creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)

{1}{W}, {T}: Aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

Whenever a creature enters, if it entered from a graveyard or a player cast it from a graveyard, return Ceaseless Stalker from your graveyard to the battlefield at the beginning of the next end step.

Flying
{2}{W}: Target Spirit creature gets +0/+1 until end of turn.

When Thallid Cultivator dies, mill four cards. Return a creature card milled this way to your hand.

Cast this spell only if an opponent controls a creature with power 5 or greater or you control six or more lands.
Return all nonland permanents target player controls to their owner's hand.

Exile target creature, then return that card to the battlefield under its owners' control.

Whenever Journeying Giftbearer or another nontoken creature you control enters, create a green and white Aura enchantment token named Wild Boon attached to that creature. The token has enchant creature and “Enchanted creature gets +1/+1.”

When Shala Na enters, each player chooses a creature they control, then sacrifices the rest.
[+1]: Up to one target creature you control gains double strike and haste until end of turn.
[–6]: You get an emblem with “Whenever a creature dies, each opponent loses 2 life.”

Enchant creature
When Bramble Armor enters, put a +1/+1 counter on enchanted creature.
{G}, Sacrifice Bramble Armor: Enchanted creature gains indestructible end of turn. Tap it.

Vigilance, reach
Deploy 5 (As this enters, you may tap any number of other creatures you control with total power 5 or more.)
When Earthly Principality enters deployed, your life total becomes equal to your starting life total plus 5.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Ash Breather deals combat damage to a player, you may discard a card. If you do, draw a card.

Whenever The Winged Steed attacks, create a 4/4 red Dragon creature token with flying that's tapped and attacking. Exile that token at end of combat.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)