msem-instigator

(As an Encounter enters, choose an opponent to protect it. You and others can attack it. When defense counters are removed, create a 0/0 Army token if you don't control one, then put that many +1/+1 counters on a Army you control.)
When Kaneh Rising enters, if you cast it, exile target creature you control, then return it to the battlefield under its owner's control. Create a token that's a copy of it. Those creatures gain haste until end of turn. Sacrifice the token at the beginning of the next end step.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Tap target creature. If this spell's tithe was paid, exile that creature.

Enchant creature
Enchanted creature gets +0/+2 and can block an additional creature each combat.

Target creature gets -3/-3 until end of turn. Its controller loses 3 life. You mill three cards.

Flash (You may cast this spell any time you could cast an instant.)
When Dazzling Voidmage enters, you may return target attacking creature to its owner's hand.

When Aerie Bell-Warden enters, if it's in a pack, you gain 5 life. (Two or more creatures you control with equal power are in a pack.)

When Bal's Descent enters, each player sacrifices a creature, discards two cards, and mills three cards.
{1}{B}{B}: Transform Bal's Descent. Activate only if your fealty to Swamps is five or greater.

During your turn, cards in your hand have cycling {X}, where X is the number of cards you've discarded this turn.
At the beginning of each end step, create a 1/1 blue Tentacle creature token for each card you discarded this turn.
Cycling {R} ({R}, Discard this card: Draw a card.)

Menace
Ferocious — Whenever Zhenya, the Draconic becomes blocked by a creature, it deals 3 damage to that creature if you control a creature with power 4 or greater.

Casualty of War deals 4 damage to target creature or planeswalker.
{2}{R}{R}, Exile Casualty of War from your graveyard: Arm up to two target creatures you control. Activate only as a sorcery. (Create a colorless Equipment artifact token with “Equipped creature gets +1/+0” and equip {2}, then attach it to that creature.)

Flying (This creature can't be blocked except by creatures with flying or reach.)
Vaporkin can block only creatures with flying.

At the beginning of your upkeep, put a brush counter on Life's Work, exile cards from the top of your library until you exile a card with mana value greater than or equal to the number of brush counters on Life's Work, then put that card into your hand.

This spell costs {2} less to cast if its target's controller is poisoned.
Counter target spell unless its controller pays {X}.

{1}{B}, Mill three cards: Return Dredging Aberration from your graveyard to your hand.

You may have Hero of Shengin Province assign its combat damage as though it weren't blocked.
{2}{G}: Until end of turn, you may have creatures you control assign combat damage as though they weren't blocked. Activate only if Hero of Shengin Province is in your graveyard.

Whenever Sirif of the Lord's Legion attacks, you may put a lore counter on target Saga you control.
Whenever Sirif deals combat damage to a player, you may remove a lore counter from target Saga you control.

When Goriana Earthshaker enters, you may untap target land you control. It becomes a 3/3 Elemental creature with haste until end of turn. It's still a land.

Whenever a token creature you control dies, each opponent loses 2 life.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
Deadland Mongrel gets +1/+1 if it engorged a creature card with power 3 or greater.

{T}: Add {C}.
{T}, Reappropriate: Add one mana of any color. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

{2}, Sacrifice another creature: Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

{T}: Add {C}.
{1}, {T}: Add {B}{G}.

This spell costs {2} less to cast if you activated an ability that's not a mana ability this turn.
Searing Grace deals 3 damage to any target.

Whenever another creature you control enters, put a +1/+1 counter on a creature you control.

{W}{B}, Shuffle Inexorable Explorer into your library: Return target creature card from your graveyard to the battlefield.
{W}{B}, Sacrifice a creature: Return Inexorable Explorer from your graveyard to the battlefield tapped.