msem-instigator

{2}, {T}, Sacrifice Tunnel Map: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Flying, lifelink
Sacrifice a creature: Until end of turn, Turned Watcher gets +1/+0 and gains “Whenever Turned Watcher deals combat damage to a player, draw a card.”

Whenever Twilight Walker perseveres, target creature doesn't untap during its controller's next untap step. (A creature perseveres when it survives damage.)

Choose one—
• Scry 3. Draw a card.
• Fateseal 3. That player draws a card. (To fateseal 3, look at the top three cards of an opponent's library, then put any number of them on the bottom of that player's library and the rest on top in any order.)

Attacking creatures have winnow. (Damage dealt to a creature with winnow also causes its controller to lose that much life.)

Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)
Revive {1}{B} ({1}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Target creature gets +3/+3 and gains winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)

Creature tokens you control get +1/+1 and have distorted. (They can be blocked by tapped creatures but not untapped creatures.)

This spell costs {X} less to cast, where X is the power of the creature it targets.
Tyrant's Reckoning deals 4 damage to target creature.

Vision (Whenever this or another creature enters the battlefield under your control, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Ulek Crusher envisions a creature card, it gets +2/+2 until end of turn.

When Ulek Elder enters the battlefield, look at the top card of your library. You may put it into your graveyard.

This spell costs {1} less to cast for each Scarecrow you control.
Other creatures you control get +0/+2 and have vigilance.

Vision (Whenever this or another creature enters the battlefield under your control, reveal the top card of your library. Then you may put that card into your graveyard.)
As Ulek Wayfinder envisions a land card, you may put that card onto the battlefield tapped.

Vision (Whenever this or another creature enters the battlefield under your control, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Ulek Windrider envisions an instant or sorcery card, it gets +1/+0 and gains flying until end of turn.

Flash
If a card or token would be put into an opponent's graveyard from anywhere, exile it instead.

This spell costs {2} less to cast if you control a Scout.
Search your library for up to two basic land cards, reveal those cards, and put one onto the battlefield tapped and the other into your hand, then shuffle.

Whenever a creature you control is dealt damage, put a +1/+1 counter on that creature.

When Uncovered Idol enters the battlefield, scry 1.
{1}, Sacrifice Uncovered Idol: Put a +1/+1 counter on target creature. Activate only as a sorcery.

When Uncovered Mine enters the battlefield and at the beginning of your upkeep, return a random card from your graveyard to your hand.

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Undercity Diplomat can't be blocked by marked creatures.

{T}, Sacrifice a permanent: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

At the beginning of your upkeep, reveal the top card of your library. If it has the same name as a card in your graveyard, put the revealed card into your hand. Otherwise, put it into your graveyard.

Undine Coven gets +1/+1 for each other Merfolk you control.
Whenever you cast a noncreature spell, Undine Coven deals 1 damage to target player or planeswalker.

Menace
{3}{B}, Discard a card: Unhallowed Singers gets +3/+0 until end of turn. Whenever it deals combat damage to a player this turn, they discard a card.