msem-instigator

The first instant or sorcery spell you cast each turn has convoke. (Each creature you tap while casting that spell pays for {1} or one mana of that creature's color.)

Deathtouch
When Backstage Comic enters, target player discards a card.

Lifelink
Whenever Backstage Prompter deals combat damage to a player, put a +1/+1 counter on it.

When Backwoods Cultivator enters, put a +1/+1 counter on target creature you control.
When Backwoods Cultivator dies, proliferate. (You choose any number of permanents and/or players with counters on them, then give each another kind of a counter already there.)

Deathtouch
Bahet's Emissary gets +1/+1 as long as you control a white or black permanent.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
Flying
{1}{W}: Demigod — Return up to one target creature card with mana value 2 or less from your graveyard to the battlefield.
{3}{W}: God — Put a +1/+1 counter on each creature you control with the least power among creatures you control.

Flying, deathtouch

Reach
{4}{B}: Each opponent loses 2 life and you gain 2 life.

Trample
When Bank Skimmer enters, create a green Aura enchantment token named Turtle's Valor attached to target creature. The token has enchant creature and “Enchanted creature gets +X/+X, where X is its mana value.”

Battalion — Whenever Barbarian Rager and at least two other creatures attack, Barbarian Rager gets +2/+0 until end of turn.

{2}{B}, Exile Barbed Cocoon from your graveyard: Create two 1/1 green Insect creature tokens. Activate only as a sorcery.

Vanguard — Whenever a creature you control attacks alone, it gets +1/+3 until end of turn.

Vigilance
Whenever Bartimus attacks, another target attacking creature gets +1/+1 until end of turn. If that creature is a Soldier, put a +1/+1 counter on it instead.

Batrest, Fellor Leader gets +1/+1 for each Equipment attached to it.
When Batrest enters, create Astrina, Forged for Glory, a legendary colorless Equipment artifact token with “Equipped creature gets +4/+4 and has first strike and lifelink” and equip {4}. Attach it to Batrest.

When Battlefield Tiger enters, create two 1/1 white Soldier creature tokens.

Deathtouch, lifelink
Whenever Batwing Initiate deals combat damage to a player, put a +1/+1 counter on it.
Pay 4 life: Batwing Initiate gains flying until end of turn.

Bearer of Fables gets +1/+1 for each enchantment you control.
{2}{G}: Look at the top four cards of your library. You may reveal an enchantment card or a card with fabled from among them and put it into your hand. Put the rest on the bottom of your library in any order.

When Bearer of Silk Chains enters, gain control of target nonland permanent until Bearer of Silk Chains leaves the battlefield. If that permanent is a Horror, gain control of it instead.

When Bearer of Tormented Truths enters, look at target player's hand. You may exile a nonland card from among them. If you do, that player draws a card.
You may play cards exiled with Bearer of Tormented Truths, and you may spend mana as though it was mana of any color to cast them.

{T}: Add {G}.
{T}: Add {G}{G}. Activate only if you control an Elemental.

{2}{G}: Target face-down creature you control becomes a Beast with base power and toughness 5/5 until end of turn.

Whenever Beatrice's Dodger attacks, create a 1/1 black and red Human Rogue creature token that's tapped and attacking.
{3}{B}{R}: Return Beatrice's Dodger from your graveyard to the battlefield
tapped and transformed.

When Bellani Mystic enters, target player mills two cards.

Whenever another creature you control dies, put a +1/+1 counter on Belligerent Mob.

{T}: Until end of turn, target land is every basic land type in addition to its other types and its name becomes Morphic Sea.