msem-instigator

Trample
When Dogged Pioneer enters, create a 2/2 green Hound creature token.
Whenever a land you control enters, put a +1/+1 counter on Dogged Pioneer and up to one target Hound.

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

Whenever a creature deals combat damage to you, that creature's controller gains control of Nightmare Alley.
{T}: Add {C}.
{1}, {T}: Target attacking creature gets +1/+0 until end of turn and can't be blocked this turn.

Whenever a creature dies, put a +1/+1 counter on each creature you control with power less than it.
{3}{G}, Sacrifice a creature: Draw cards equal to the sacrificed creature's power.

{2}: Sparkline Dancer gains flying until end of turn.

Enchant creature
When Mesmerizing Shimmer enters, untap enchanted creature. It gains haste until end of turn.
You control enchanted creature.
Mirage {2}{U}{R} (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Choose one —
• Target creature gets +4/+2 until end of turn.
• Pyromantic Expertise deals 4 damage to target creature or planeswalker.

Up to one target creature can't block this turn. (Then exile this card. You may play the land later from exile.)

Advance {3}{W} (Cast this for {3}{W} to advance it as it enters. {3}{W}: Advance this as a sorcery.)
Whenever Hrexa Enforcer advances, put a +1/+1 counter on it.

Create a number of 3/3 green Elemental creature tokens equal to the number of differently named lands you control.
Fuse (You may cast one or both halves of this card from your hand.)

Fall of the Axe deals 3 damage to any target.

Menace, deathtouch
Whenever a creature an opponent controls dies, that player loses 2 life and you gain 2 life.

Target player draws seven cards, then their life total becomes equal to the number of cards in their hand.

Whenever you gain life, Clerics you control get +1/+1 and gain trample until end of turn.

Exile target creature. If you controlled that creature, create a 4/4 red Dragon creature token with flying. Otherwise, its controller creates a 1/1 white Bird creature token with flying.
Showcase {4}{U} (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.)

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
Whenever you cast an enchantment, instant, or sorcery spell, Noble Barracuda gets +1/+0 until end of turn. Scry 1.

Target opponent loses 1 life for each creature they control. You gain 2 life for each Wizard you control.

Flash
Deathtouch

When Tinyvale Trappings enters, you may attach it to target creature you control with mana value 2 or less.
Equipped creature gets +3/+1.
Equip {3}

{T}, Pay 1 life: Add {W} or {U}.
{1}, {T}, Sacrifice Cleared Vault: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Ferocious — Whenever a creature with power 4 or greater you control enters, Mieng, Who Dances With Dragons becomes a 4/4 Dragon creature with flying until end of turn.

Creatures you control get +2/+0 until end of turn. Creatures you control with counters on them gain trample until end of turn.

When Keeper of Dark Shadows enters, if it's not a token, target opponent reveals their hand. You may choose a creature card from it. Create a token that's a copy of that card, except it's a colorless Spirit.

Creatures you control get +2/+2 until end of turn.

Counter target spell.
Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)