msem-instigator

Deathtouch
Whenever Ruststep Centipede deals combat damage to a player, you may destroy target artifact or enchantment that player controls.

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.)
Ruthless Predator can't be blocked by more than one creature.

{T}, Sacrifice a creature: Conjure a card named Data-Point into your hand. Activate only as a sorcery. (It's a sorcery that costs {2} with “Draw a card.”)

Haste
Whenever an embattled creature you control deals combat damage to a player, you may pay {2}{G}. If you do, create a token that's a copy of that creature, except the token isn't legendary if the creature is legendary. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

When Sabne's Autumn enters, search your library for a Forest card, reveal it, put it into your hand, then shuffle. You gain 3 life.
{1}{G}{G}: Transform Sabne's Autumn. Activate only if your fealty to Forests is five or greater.

Indestructible
Lands you control have “{T}: Add {G}{G}.”
{5}{G}{G}: Double the power and toughness of each creature you control until end of turn.

{G}: Exile target card from a graveyard. If it was a land card, put a +1/+1 counter on Sacrificial Bull.
{G}, Sacrifice Sacrificial Bull: You gain life equal to its power.

Trample
When Saddlesaur Guide enters, create a green Aura enchantment token named Hefty Load attached to target creature. The token has enchant creature and “Enchanted creature gets +2/+2 and has trample.”

Return target creature or land card from your graveyard to your hand. You may shuffle up to three cards from your graveyard into your library.

Whenever a creature in Sage of Circular Motion's pack becomes the target of a spell, draw a card. (Two or more creatures you control with equal power are in a pack.)

Whenever Sage of Reflections attacks, mill three cards, then choose a creature card milled this way. Create a token that's a copy of it that's tapped and attacking, except it has no mana cost.

Whenever a land creature you control deals combat damage to a player, put a +1/+1 counter on it.
{1}{G}: Put a +1/+1 counter on target land you control. It becomes a 0/0 Elemental creature that's still a land.

Trample
Whenever Saghira, Divinity's Usurper attacks, you may pay {1}{G}. If you do, destroy target artifact, enchantment, or creature with flying.

Vigilance
{1}{G}{G}: Sahalia Dragoons gets +4/+4 until end of turn. Activate only once each turn.

Trample
When Sahra's Crusher enters, judge another target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

Survivors you control get +2/+2.

Deathtouch

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Destroy target creature with flying.

Trample
You may cast Sandswim Titan from exile. If you do, it enters with three +1/+1 counters on it.

Choose two —
• Target player creates a 3/3 green Wurm creature token.
• Target player puts three +1/+1 counters on a creature they control.
• Return target permanent card from your graveyard to your hand.
• Destroy target creature with flying.

When Sandwurm's Might enters, you may have target creature you control fight target creature you don't control.
Each creature you control enters with an additional +1/+1 counter on it.

Flash
Poisonous 2 (Whenever this creature deals combat damage to a player, that player gets two poison counters. A player with ten or more poison counters loses the game.)
When Sankataar Ambusher enters, if an opponent is poisoned, Sankataar Ambusher gets +2/+2 until end of turn.

Poisonous 3 (Whenever this creature deals combat damage to a player, that player gets three poison counters.)
When Sankataar Assailant enters, choose a counter on target permanent or player. Give that permanent or player another counter of that kind.

Poisonous 2 (Whenever this creature deals combat damage to a player, that player gets two poison counters.)
Sankataar Coilborn gets +1/+1 as long as an opponent is poisoned.

Create X 1/1 green Saproling creature tokens, then populate. (Create a token that's a copy of a creature token you control.)