msem-instigator

({T}: Add {U}.)
As Seaside Grotto enters, you may pay 1 life. If you don't, Seaside Grotto enters tapped.
Basic lands you control have “{T}: Add {U}.”

When Himari enters, put a +1/+1 counter on a creature you control.
Creatures you control with counters on them have base power and toughness 4/4 and have trample.

Gain control of target artifact, creature, or planeswalker if its mana value is 4 or less or if you cast A Sucker for You from a graveyard.
Reconstruct {9}{U}{U}{U} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

First strike, menace
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
At the beginning of each combat, you may pay {1}. When you do, another target creature gains melee until end of turn. (If a creature has multiple instances of melee, each triggers separately.)

You can't cast this spell unless you have at least 5 life more than your starting life total.
Ward—Pay 5 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 5 life.)
{3}{W}{B}, Discard Life's Bride: Exile target nonland permanent. You gain life equal to its mana value.

Draw a card, then forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

Target player sacrifices an attacking or blocking creature. Prevent all damage that would be dealt by creatures this turn.

Fiendish Yaoguai can't block.
Scavenge {5}{B} ({5}{B}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

Destroy target artifact or land. If a land was destroyed this way, its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Target creature you control gets +3/+3 and gains lifelink and trample until end of turn.
Inscribe {3}{G}{W} ({3}{G}{W}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Vigilance
Avatar of Utsenchep can block any number of creatures.
All creatures able to block Avatar of Utsenchep do so.

Prowess
Whenever Balefire Conjurer attacks, you may pay {1}{R}. If you do, exile the top card of your library. You may play that card until the end of your next turn.

Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy. Overclock deals X damage to you, where X is the number of spells you've cast this turn.

When Ramzi, Traveling Merchant enters, adjudicate land. (Create a white enchantment Aura token with enchant land and “Sacrifice this token: Untap enchanted land.” attached to target land.)
Whenever an Aura becomes attached to a land you control, create a 1/1 green Antelope creature token.

For each pair of basic land types, create a tapped colorless land token of those types. (The basic land types are Plains, Island, Swamp, Mountain, and Forest.)

Menace (This creature can't be blocked except by two or more creatures.)
{1}{R}: Wandering Goliath gets +1/+0 until end of turn.

Whenever a player casts an instant or sorcery spell that targets only one target or activates an ability that targets only one target, copy that spell or ability for each other target it could target. Each copy targets a different one of those targets. (A spell or ability can't target itself.)

When Luna enters, you may put a +1/+1 counter or loyalty counter on target creature or planeswalker.
Whenever another creature or planeswalker enters, you may exile Luna. Return her to the battlefield at the beginning of the next end step.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Scourge of the Deadlands enters, if it engorged a creature card, each other player sacrifices a creature.

When Globule of Vigor enters or leaves the battlefield, up to one target creature gets +1/+1 until end of turn.
{2/G}, {T}, Sacrifice Globule of Vigor: Draw a card.

Barren Vista enters tapped.
{T}: Add {U} or {B}.
{1}, {T}: Add one mana of any color.

When Debt Dignitary enters, tap target nonland permanent. That permanent doesn't untap during its controller's untap step for as long as you control Debt Dignitary.

Creatures your opponents control can't block alone. (They can block different creatures.)

First strike, lifelink

Non-Actor creatures can't block this turn.