msem-instigator

Menace
Whenever you discard a card, Stillsong Enforcer deals 1 damage to target opponent or planeswalker.

Haste
Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)

Flying
{1}{R}{R}{R}: Return Umbral Hunter from your graveyard to your hand. If it's the declare attackers step, up to one target attacking creature gets +3/+1 until end of turn.

Trample
Whenever Unruly Cannoneer crews a Vehicle, that Vehicle gets +1/+1 and gains trample until end of turn.

First strike
Wither (This deals damage to creatures in the form of -1/-1 counters.)

Menace
Ferocious — Whenever Zhenya, the Draconic becomes blocked by a creature, it deals 3 damage to that creature if you control a creature with power 4 or greater.

When Border Seeker dies, search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then you gain 1 life for each land you control.

When Caravan Guard enters, for each kind of counter on target permanent, put another counter of that kind on it or remove one from it.

Distorted (This creature can be blocked by tapped creatures but not untapped creatures.)

Whenever you cast a noncreature spell, you may shuffle target card an opponent owns in exile into its owner's library.

Elfcycling {2}{G} ({2}{G}, Discard this card: Search your library for an Elf card, reveal it, and put it into your hand, then shuffle.)

When Fallspeaker Satyr enters or dies, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Whenever a creature you control enters for the second time each turn, it gains haste until end of turn. You may have it get +1/+1 until end of turn.

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Trample

Trample, haste
When Relonche Cavalry enters, other creatures you control get +1/+0 and gain trample and haste until end of turn.

Trample
Chosen one ({W}{U}{B}{R}{G}: Transform this permanent.)

When Shifty Squirrel enters, you gain 3 life.
Sacrifice a creature: Transform Shifty Squirrel.

Whenever Unbudging Badger attacks, if its power is 4 or greater, it gains trample until end of turn.

Remove a +1/+1 counter from a creature you control: Regenerate Verendas Brawler. (The next time this creature would be destroyed this turn, it isn't. Instead tap it, remove all damage from it, and remove it from combat.)

Alpha (You may have this creature enter with a +1/+1 counter on it. If you do, it becomes alpha and can only attack alone.)
Vigilance

Ferried Stagecoach can't be blocked as long as another creature is attacking.
Whenever Ferried Stagecoach deals combat damage to a player, each player flips a coin. Each opponent that loses the flip discards a card, and each player on your team that wins the flip draws a card.

Flash
Flying
Whenever a player discards a card, you draw a card. This ability triggers only once each turn.

Whenever you cast a spell from anywhere other than your hand, return Ruthless Bakhtak from your graveyard to your hand.

Haste
When Bloodfury Warlord enters or dies, it deals 2 damage to each player.

Menace, haste
Whenever another creature dies, you get a blood counter.
{B}{R}, Pay two blood counters: Return Dthan, Who Bloodies the Sands from your graveyard to the battlefield.