msem-instigator

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Northwind Master enters, you may have another target creature you control gain prowess until end of turn.

When Null Paradigm enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)
Whenever you cast a sorcery spell, each opponent loses 1 life and you gain 1 life.

Tap target creature. That creature doesn't untap during its controller's next untap step.

Enchant creature
Whenever you cast a green spell, enchanted creature gets +2/+2 until end of turn.

Equipped creature has “{T}: This creature deals 1 damage to any target.”
Equip {3}

{T}: Put a luster counter on Object of Awe.
{1}{R}, {T}: Discard up to X cards, then draw a card for each card discarded this way. X is the number of luster counters on Object of Awe.
{3}{R}: Until end of turn, Object of Awe becomes an X/X red Phoenix creature with flying, where X is the number of luster counters on Object of Awe.

Attacking creatures get -2/-0 until end of turn.
Metamorph {1}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{T}: Salvage a creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Motley — At the beginning of combat on your turn, if there are five or more names among nonland permanents you control, Ochre Knight gets +2/+1 until end of turn and you gain 1 life.

Ode to the Red Wind deals 1 damage to target creature. It can't block this turn.
Showcase {3}{R} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Each player sacrifices a creature. If a player lost 3 or more life this turn, each opponent sacrifices a creature instead.

{T}: You may put a land card from your hand onto the battlefield.
{1}, {T}: Aetherize target land you control. (To aetherize, create a token that's a copy of it, then exile that token.)

Target creature gets -X/-X until end of turn, where X is the number of enchantments you control.

When Old-Oath Conviction enters or leaves the battlefield, create a 1/1 white Cleric creature token with lifelink.
{3}{B}, Sacrifice Old-Oath Conviction: Draw a card. Activate only as a sorcery.

Return target creature card with mana value 3 or less from your graveyard to the battlefield. If its mana value is less than 3, you gain life equal to the difference.

Target creature you control gains haste until end of turn. Return it to its owner's hand at the beginning of the next end step.

Enchant creature
Whenever enchanted creature deals combat damage to a player, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. Scry 2.

Whenever Ontarachie Hunter attacks, each opponent loses 1 life.
At the beginning of your end step, if an opponent has 10 or less life, transform Ontarachie Hunter.

Whenever Open Road or another permanent you control enters, if it has the greatest mana value among permanents you control, you may discard a card. If you do, draw a card.

{T}: Add {G}. If you control an attacking creature, add one mana of any color instead.

Enchant creature
Enchanted creature can't attack or block unless its controller pays {3}.
Activated abilities of enchanted creature cost {3} more to activate.

Scry 1.
Draw a card.

When Oracle Crab enters, scry 2. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.)

Search your library for up to six cards and exile them face down. Shuffle, then draw a card.