msem-instigator

When Drownyard Scavenger enters, each player may return an instant or sorcery card from their graveyard to their hand.

Equipped creature gets +1/+0 and has first strike.
As long as another artifact named Dueling Blades is attached to a creature you control, equipped creature has double strike.
Equip {1}

(As an Encounter enters, choose an opponent to protect it. You and others can attack it. When defense counters are removed, create a 0/0 Army token if you don't control one, then put that many +1/+1 counters on a Army you control.)
When Settling of Nizev enters, look at the top four cards of an opponent's library, exile two of them, and put the rest on the bottom of their library in a random order. You may play those cards for as long as they remain exiled, and mana of any type can be spent to cast them.

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
When Bloodchill Risen enters, if it engorged an instant card, return target creature to its owner's hand.

Whenever a land you control enters, you may pay {1}. If you do, create a 1/1 green Saproling creature token.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever Steelhoof Battlechief attacks, another target attacking creature you control gets +2/+2 and gains trample until end of turn.

Whenever a creature you control dies, destroy target creature you don't control.

Flash
When Surreal Bakhtak enters, choose one —
• Destroy target tapped creature.
• Tap up to three target creatures.

Target creature gains hexproof until end of turn.
Create a colorless artifact token named Lotus Petal with “{T}, Sacrifice this artifact: Add one mana of any color.”

[+1]: Add {R} or {G}. You can't spend this mana to cast an Elf spell.
[–2]: Winona, the Heretic deals 4 damage to any target. If that target is an Elf, Winona deals 4 damage to that Elf's controller.
[–6]: Until end of turn, any time you could cast an instant, you may pay {R}. When you do, Winona deals 2 damage to any target.

Activated abilities of sources you don't control can't be activated unless they're mana abilities.

{1}{W}, {T}: Tap target creature.
Put a -1/-1 counter on Insistent Ingenue: Untap Insistent Ingenue.

Move up to one +1/+1 counter from a creature you control to target creature you control. Then that creature fights target creature you don't control.

[+1]: Haide Bankbuster deals 2 damage divided as you choose among one or two targets.
[+1]: Draw two cards unless any player has Haide Bankbuster deal 3 damage to them.
[–9]: Until end of turn, gain control of all permanents target player controls and they gain haste. Untap those permanents.

Flying
Spirited (When this creature enters, you may activate one of its activated abilities without paying its cost.)
{3}{U}: Target creature you control gains flying until end of turn.

Avaz Sanctuary enters tapped.
Satrapies you control have “{T}: Add {R} or {W}.”

Giant's Temple enters tapped.
{T}: Add {G}.
{2}{G}, {T}: Target nonland permanent you control becomes a creature with power and toughness equal to its mana value until end of turn. (It loses all other types.)

When Herald of Teardrops enters, choose one. If you control another Elemental, you may choose both instead.
• Create a 1/1 blue Elemental creature token with flying.
• Put a +1/+1 counter on each of up to two creatures.

Wharf Lumper can't be blocked by creatures with greater power.
Whenever Wharf Lumper attacks, mill a card. If that card was an instant or sorcery, Wharf Lumper gets +3/+0 until end of turn.

When Hamlet Bounder enters, choose one —
• Destroy target artifact or enchantment.
• Create a 1/1 white Peasant creature token.

Flash
When Issbarren Warden enters, exile target token.

Wild Ravine enters tapped unless you control two or more red and/or green permanents.
{T}: Add {R} or {G}.

Settle the Dust deals 4 damage to each tapped creature.

Assault {1}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
When Bone Mesa Marauder assaults, it gains flying until end of turn.

Equipped creature gets +1/+1 and has flying and haste.
Equip {3}