msem-instigator

Choose one —
• Counter target spell unless its controller pays {X}.
• Surveil X, then draw a card.

Counter target spell unless its controller pays {1}.

Put a +1/+1 counter on target creature. It gains indestructible until end of turn.

Search your library for a Demon card or a black card with mana value 6 or greater, reveal it, put that card in your hand, then shuffle.

Target creature you control gets +2/+2 until end of turn. If it's blocked or blocking, it gets an additional +2/+2 until end of turn.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)

When Jaakuna Bloodsworn enters, any opponent may have it deal 3 damage to them. If a player does, sacrifice Jaakuna Bloodsworn.

{1}, {T}: Put a +1/+1 counter on Jade Sentinel. Activate only if you control a creature with power greater than Jade Sentinel's.

As long as Jadycian Empath is on the battlefield or in your graveyard, it's a land in addition to its other types.
Sacrifice Jadycian Empath: Add one mana of any color.

Menace
Jara Champion can only attack or block alone.
Whenever one or more players lose life for the first time each turn, put a +1/+1 counter on Jara Champion.

Advance {2} (Cast this for {2} to advance it as it enters. {2}: Advance this as a sorcery.)
Equipped creature gets +X/+0 and has flying, where X is the number of times it and Jet Pack have advanced this turn.
Equip {1}

Return target creature card from your graveyard to your hand. Catalyze. (The next spell you cast this turn costs {1} less to cast.)
Flashback {3}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

When Journey to Elrayin enters, journey, then choose a creature card name. (To journey, exile the top card of your library face up. Whenever a creature you control deals combat damage to a player, put a journeyed card you own into your hand.)
Whenever a creature you control with the chosen name deals combat damage to a player, journey.

Detain target creature. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)
Scry 1.

Target player sacrifices a legendary creature or planeswalker.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
Jutou enters with X +1/+1 counters on her.
{3}{G}: Demigod — You gain life equal to the greatest power among creatures you control.
{6}{G}: God — Search your library for a creature card with the same power as a creature you control, put it onto the battlefield, then shuffle.

Equipped creatures you control get +1/+1.
Equip {2}

Prowess
You may activate inscribe abilities from your graveyard as though they were in your hand.

Kamito Pathseeker can't block.
{3}{R}, Exile Kamito Pathseeker from your graveyard: Return target instant or sorcery card from your graveyard to your hand.

Whenever you cast a noncreature spell, you may pay {R}. If you do, untap Kamito Rageweaver.
{T}: Kamito Rageweaver deals 1 damage to target player.

{T}: Kanaan Wardriver deals 1 damage to target creature you control. That creature gains haste until end of turn.

When Kaneh Headdress enters, create a 1/1 blue Advisor creature token, then scry 1.
Equipped creature gets +1/+1.
Equip {2}

Exile target creature or planeswalker. Its controller may search their library for a creature or planeswalker card and reveal it, then shuffle and put that card on top.

Whenever Karoa, His Roaring Grace deals combat damage to a player, if he's not equipped, create a colorless Equipment artifact token named Banner attached to him. The token has equip {1} and “Equipped creature gets +1/+1.”

Flash
Enchant creature
Whenever enchanted creature becomes the target of an ability or spell you don't control or leaves the battlefield, enchanted creature deals 3 damage to any target.