msem-instigator

{T}: Add one mana of any color. If you spend this mana to cast a face-down creature spell, you gain 2 life.

When this artifact enters, target creature you control seeks secrets. (Give it that Oath Aura. Fulfill it by attacking with it and two or more other creatures to draw a card.)
Equipped creature gets +2/+1. As long as it has an Oath attached to it, it has menace.
Equip {3}

{2}: Dragonfire Longboat gets +1/+0 until end of turn.
Crew 1 (Tap any number of creatures you control with total power 1 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

({T}: Add {R} or {G}.)
As Ruptured Trail enters, you may pay {1}. If you don't, Ruptured Trail enters tapped.

As Choked Estuary enters, you may reveal an Island or Swamp card from your hand. If you don't, Choked Estuary enters tapped.
{T}: Add {U} or {B}.

Whenever you cast a legendary spell, each opponent loses 1 life and you gain 1 life.
{W}{B}, Sacrifice a legendary nonland permanent: Draw two cards.

You may have Imitator of Success enter as a copy of any creature on the battlefield, except it has no mana cost and base power and toughness 1/1 if it's a token.
Successor {1}{U}{U} ({1}{U}{U}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost and base power and toughness 1/1. Succeed only as a sorcery.)

When Mettalia's Forward enters, you may salvage a card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

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.

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.
{4}{B}, Pay 3 life, Sacrifice Traverse the Endless Well: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

Lieshi Shrine enters tapped.
{T}: Add {W} or {B}.
{W/B}, {T}, Sacrifice Lieshi Shrine: Put a +1/+1 counter on target creature you control. Activate only as a sorcery.

Lifelink
Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

At the beginning of your upkeep, mill a card.
Whenever a creature card is put into your graveyard from your library, you may exile it. If you do, create a 2/2 black Zombie creature token.

(Transform this if it's not attached to a creature. Pay {3}{B} as a sorcery to unattach it.)
Enchant creature you control
Corrupted Mount's rider gets +5/+4 and can't block.

Trample

({T}: Add {W} or {U}.)
As Ruptured Square enters, you may pay {1}. If you don't, Ruptured Square enters tapped.

As Citadel Gates enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}, {R}, or {G}.

Each player sacrifices a creature. Purge. (Exile two cards that share a type from graveyards. If you do, draw a card.)

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Lifelink
Revelation spells you cast cost {1} less to cast.

Enchant creature
Enchanted creature has experience. (Whenever it attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)

Sacrifice Kumo-no-Oni: Prevent all combat damage that would be dealt this turn.

Flying
Sire of Empires gets +1/+1 as long as you control another creature, has lifelink as long as you control an enchantment, and has vigilance as long as you control an artifact.

Ambitious Ostrich has flying as long as you control a storied permanent. (Enchantments and legendary permanents are storied.)

Counter up to one target spell unless its controller pays {2}. Until end of turn, you may cast spells as though they had flash.