msem-instigator

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

Equipped creature gets +2/+0 and is a Dragon in addition to its other types.
Equip {1}

When Impervious Fortifications enters, you gain life equal to the number of creatures you control.
Creatures can't attack you or a planeswalker you control unless their controller pays {2} for each creature they control that's attacking you.

Flying, lifelink
Whenever another creature you control attacks, until end of turn, that creature gets +2/+0 if it's red, +0/+2 if it's green, gains lifelink if it's white, and gains flying it if it's blue.

Whenever you make first contact, Abrasive Citizen gets +3/+0 until end of turn. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Wild Haploc has first strike as long as it's attacking.

Flying
When Ameret's Favored enters, you gain 3 life.

Tap any number of untapped creatures you control. You gain 4 life for each creature tapped this way.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Towering Wickerman can't be blocked by creatures with power 2 or less.
Whenever a creature merges with Towering Wickerman, put two +1/+1 counters on it.

Archive 4 (As this enters, shuffle the top four cards of your main library into a new face up library. Sacrifice this after the archived library is empty.)
Whenever you draw a card from the archived library, gain control of target nonland permanent with a lesser mana value than that card until you draw a card from the archived library.

Whenever another creature you control enters, put your choice of a vigilance, reach, or trample counter on this creature.
{T}, Remove a counter from this creature: Add one mana of any color. If that mana is spent on a creature spell, you may have it enter the battlefield with an additional counter of that kind on it.

{W}{B}{G}, Discard a card named Bahet, God of Destruction: Bahet gains indestructible and becomes a God creature in addition to its other types.
Whenever Bahet enters or attacks, each player chooses a number of lands they control equal to the number of lands controlled by the player who controls the fewest, then sacrifices the rest. Players discard cards and sacrifice non-God creatures the same way.

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a noncreature spell, target creature can't block this turn.

{T}: Add {U}. Spend this mana only to activate an ability or cast an instant or sorcery spell.

Whenever an opponent activates an ability of a permanent, if it isn't a mana ability, you gain 1 life and create a Gold token. (It's an artifact with “Sacrifice this artifact: Add one mana of any color.”)

As long as you have 25 or more life, Alia's Enforcer gets +2/+2 and gains flying.
Whenever an artifact or enchantment you control enters, you gain 1 life.

Gestalt (When this or another creature enters under your control, you may merge it with the one in play, keeping counters and attachments. They become the permanent on top plus all abilities from under it.)
Whenever this creature attacks, if it's merged with another card or token, it deals 2 damage to target player or planeswalker.

Draw two cards.

When this creature enters, put two -1/-1 counters on a creature you control.
{T}, Sacrifice another creature: Add {C}{R}. Spend this mana only to cast creature spells or activate abilities of creatures or creature cards in your graveyard.

Put two +1/+1 counters on target creature you control. When you do, it deals damage equal to its power to up to one target creature with flying.

Equipped creature gets +2/+1.
Whenever equipped creature blocks or becomes blocked by a creature, it deals 2 damage to that creature.
Equip {2}

When Dawnhart Ceremony enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Invocation — When you spend four or more mana to cast a spell or activate an ability during your turn, transform Dawnhart Ceremony.

Flying
When Rallywing enters, creatures you control get +1/+1 until end of turn.

Whenever Font of Strength enters or is put into a graveyard from the battlefield, target creature you control gets +3/+3 until end of turn.

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