msem-instigator

Whenever Knight of the Stag deals combat damage to a player, you may sacrifice it. If you do, search your library for a white legendary creature card, reveal it, put it into your hand, then shuffle.

Forgotten Consequences deals 2 damage to target attacking or blocking creature.

Protection from Clerics (This creature can't be blocked, targeted or dealt damage by Clerics.)

This spell has flash as long as you control a Monk.
When Ssytai enters, return target spell or creature you don't control to its owner's hand.

When Living Hoard enters, create a Treasure token.
{R}, Sacrifice an artifact: Living Hoard gets +2/+0 until end of turn.

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.

At the beginning of your first upkeep each turn, choose one —
• Replace your first main phase this turn with an additional upkeep step.
• Replace your second main phase this turn with an additional combat phase.

Menace, haste
As long as Arleigh, Spellblade Prodigy is tapped, the first spell you cast during each other player's turn costs {U/R} less to cast. This effect reduces only the amount of colored mana you pay. (For example, if you cast a spell with mana cost {1}{R}, it costs {1} to cast.)

Whenever Skeigr, Skhorvall Flagship attacks, it deals 3 damage divided as you choose among one, two, or three targets.
Crew 3 (Tap any number of creatures you control with total power 3 or greater: This Ship Vehicle becomes an artifact creature until end of turn.)

Flying
Whenever a creature you control dies, each opponent loses life equal to its power.

[+1]: Add {C}. Spend this mana only to cast artifact or colorless spells.
[0 ]: Create a 1/1 colorless Construct artifact creature token.
[–2]: Look at the top six cards of your library. You may reveal an artifact or colorless card from among them and put it into your hand. Put the rest on the bottom in a random order.

Indestructible
As long as your devotion to blue and red is less than seven, Keranos isn't a creature.
Whenever you cast an instant or sorcery spell, you may copy that spell. Do this only once each turn. You may choose new targets for the copy.

As Toxic Spring enters, you may tap an untapped creature you control. If you don't, Toxic Spring enters tapped.
{T}: Add {U} or {B}.

Create a Treasure token.
Showcase {2}{R} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Flying
When Kai'Dwo, Eternal Ravager enters, create seven Idol tokens. (They're artifacts with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)
Whenever you sacrifice an Idol, each opponent sacrifices a creature.

({T}: Add {U} or {R}.)
Whenever Crystal Cavern becomes tapped, you lose 1 life unless you control two or more basic lands.

At the beginning of the next upkeep, untap all noncreature permanents you control and draw a card.
Exile Tempus Fugit.

Create X 1/1 green Saproling creature tokens, then populate. (Create a token that's a copy of a creature token you control.)

{T}: Add {G}.

First strike
Whenever Ren deals combat damage to a player, you may activate one of her abilities by paying 3 life rather than paying its cost.
{1}{R}, Discard a card: Draw a card.
{2}{B}, Sacrifice a creature: Each opponent sacrifices a creature.

Target creature you control fights target creature you don't control. (Then exile this card. You may cast the creature later from exile.)

Abandoned Hideout enters tapped if you control another nonbasic land.
{T}: Add {U} or {R}.

{G}{U}{R}, Discard a card named Ifram, God of Chaos: Ifram gains indestructible and becomes a God creature in addition to its other types.
Whenever Ifram enters or attacks, choose target non-God permanent. Its owner shuffles it into their library, then its controller reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Flash
Thorn-Touch Abomination enters with X +1/+1 counters on it.

Prowess, trample
During your turn, each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost plus “Pay X life, where X is this card's mana value.”