msem-instigator

Whenever Babbling Experiment or another creature you control enters, target player mills two cards.

Whenever Merciless Shieldbreaker enters or attacks, target opponent puts three rust counters on a permanent they control with no rust counters on it. That permanent gains “At the beginning of your upkeep, remove a rust counter from this permanent. Then if there are no rust counters on this permanent, sacrifice it and it deals 4 damage to you.”

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.)
When Xiejuan, the Regal Beast becomes alpha, draw a card for each other creature you control.

This spell costs {1} less to cast for each card you've drawn this turn.
You may reveal a land card from outside the game and put it into your hand. If it's basic or a Desert, put it into the battlefield instead.

Return target creature to its owner's hand. If you controlled that creature, draw a card.

Whenever a Survivor you control enters, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

Creatures you control gain flying until end of turn if you control a creature with flying. The same is true for first strike, double strike, haste, hexproof, indestructible, lifelink, trample, vigilance, and prowess.

Hexproof
Whenever attackers are declared, the active player may pay {2} for each creature attacking you. Then you may have Bridge Kalak become an X/X Troll creature until end of turn, where X is the number of times that player didn't pay mana this way.

Flying, ward {3}
Whenever Sphinx of Myriad Futures attacks, look at the top three cards of your library and reveal one of them. The defending player may have you put the revealed card into your hand. If they don't, put the other two cards into your hand. Then put the remaining cards into your graveyard.

Trample
Whenever Gavony Cavaliers enters or attacks, create a Weapon token. (It's an Equipment artifact with “Equipped creature gets +1/+1” and equip {2}.)
Creatures you control that are enchanted or equipped have trample.

Obscoriate deals 4 damage to target creature or planeswalker. The next time that permanent would die this turn, instead put a basalt counter on it, it becomes a Mountain land named Charred Remains, loses all other card types, and gains “At the beginning of your upkeep, Charred Remains deals 1 damage to you.” (It has “{T}: Add {R}” and loses abilities it already had.)

Flying
Whenever a permanent you control is returned to your hand, scry 1.

{T}: Target creature loses all abilities until end of turn. Exile Chochin the Silent Moth and that creature.

Whenever you create one or more tokens, put a +1/+1 counter on target creature you control.
{2}{G}{W}: Create a 0/1 green Plant creature token.

Instant, sorcery, and legendary spells you cast cost {1} less to cast.

Destroy target untapped creature.

Flourishing Mountain enters tapped.
As Flourishing Mountain enters, choose a basic land type.
Flourishing Mountain is the chosen type in addition to its other types.

Flash
When Threadripper Savant enters, put a stun counter on up to one target creature.

Vigilance
Resolute — Whenever East Ward Champion attacks, attacking creatures you control gain indestructible until end of turn if East Ward Champion's power is greater than its base power.

Flying
Suisei the Southern Star gets +1/+1 for each comet counter you have.
Whenever you cast an instant or sorcery spell with mana value greater than the number of comet counters you have, you may pay {R}. If you do, return Suisei from your graveyard to the battlefield, then you get a comet counter.

At the beginning of each opponent's end step, if no spells controlled by that player resolved this turn, create a 1/1 blue Illusion creature token with “This gets +1/+1 for each other Illusion you control.”

When Rhudai Overseer enters, look at the top four cards of your library. You may reveal an artifact or enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Whenever a creature you control dies, Insidious Terror gets +1/+0 and gains menace until end of turn.

Haste
When Kragnoss, Rebellion Commander enters, create a 1/1 red Goblin creature token.
Whenever a Goblin you control attacks, Kragnoss, Rebellion Commander deals 1 damage to target creature defending player controls.

Reach
Imperious Ram can't be blocked by more than one creature.