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.)

Whenever you cast an Azra spell, mill three cards.
Whenever you cast a Demon spell, you may return an Azra card with lesser mana value than that spell from your graveyard to the battlefield.

When Babyscale Bruiser enters, you may reveal a creature card from your hand. If you do, Babyscale Bruiser deals damage to target creature an opponent controls equal to the revealed card's power. That creature deals damage equal to its power to Babyscale Bruiser.

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Back-Alley Vandal desecrates a permanent, put a +1/+1 counter on Back-Alley Vandal.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)

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 Backstage Tinkers enters, you may return an artifact card from your graveyard to your hand.

Whenever Backstreet Gutter-Runner attacks, if you control another Pirate or Rogue, it deals 2 damage to each opponent.

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.)

Menace, haste

Scry X, then purge X times. You lose X life. (To purge, exile two cards that share a type from graveyards. If you do, draw a card.)

Choose two —
• Destroy up to one target enchantment.
• Exile up to one target card from a graveyard.
• You gain 4 life.
Cycling {1}{W} ({1}{W}, Discard this card: Draw a card.)

Whenever you create one or more tokens, put a +1/+1 counter on target creature you control.
{2}{G}{W}: Create a 0/1 green Plant creature token.

Haste (This creature can attack and {T} as soon as it comes under your control.)
{1}{U}: Balloon Dragoon gains flying until end of turn.

When Banishing Initiate enters, you may exile target nonland permanent you don't control until Banishing Initiate leaves the battlefield.
At the beginning of your end step, sacrifice Banishing Initiate if a card exiled with it has mana value 3 or greater.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
Baptism by Fire deals 3 damage to target creature or planeswalker. If you're in a renaissance, Baptism by Fire deals 6 damage to that permanent instead.

Trample
Whenever another Dwarf you control enters, create a colorless artifact token named Ale. It has “{T}, Sacrifice this artifact: Target creature gets +2/+0 until end of turn. Activate only as a sorcery.”

Enchant creature
Enchanted creature gets +1/+0 and has menace and “{1}{R}: This creature gets +1/+0 until end of turn.”

Battalion — Whenever Barbaric Ambusher and at least two other creatures attack, you may tap target creature.

When Barking Irons enters, if it's not a token, create a token that's a copy of it.
Equipped creature gets +2/+0.
Equip {2}

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

Equipped creature gets +2/+2.
Equip {3}

Each planeswalker you control enters with an additional loyalty counter on it.
{T}: Add {C}.

Whenever you untap a nonland permanent, put a winding counter on Barton's Pocketwatch.
{T}: Look at the top card of your library. You may put it into your graveyard. Then if Barton's Pocketwatch has twelve or more winding counters on it, exile it and take an extra turn after this one.