msem-instigator

{R}, {T}: Sandbluff Slinger deals 1 damage to any target.
Quickdraw {1}{R} (When a creature you control blocks or becomes blocked, you may cast this spell for {1}{R}.)

When Sandborn Mage enters, you may return target instant or sorcery card from your graveyard to your hand.
Mirage {2}{U}{U} (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.)

Destroy target land. Sandburst deals 1 damage to each creature without flying your opponents control.

When Sandmouth Dragon enters, another target creature you control gets +3/+0 until end of turn.
Mirage {2}{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.)

Storied spells you cast cost {1} less to cast. (Enchantments and legendary cards are storied.)

Hexproof

Haste
Sandstorm Sentinel enters with X +1/+1 counters on it, where X is your fealty to Deserts. (Each Desert you control counts toward your fealty to Deserts.)
Mirage {1}{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.)

Shimmer (Whenever this creature attacks, create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the end step.)
When Sandstrider enters, put a +1/+1 counter on target creature.

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.

Flying
{1}{R}: Sangrite Dragon gets +2/+0 until end of turn.
Sacrifice another creature: Add {R}{R}.

Menace
Cycling {R} ({R}, Discard this card: Draw a card.)

Whenever you gain life, target opponent loses that much life.

Target creature gets -3/-3 until end of turn. You gain 3 life.

Flying, lifelink
Whenever you gain life, you may have target creature get -X/-X until end of turn, where X is the amount of life you gained.

Flash (You may cast this spell any time you could cast an instant.)
When Sanguine Muralist enters, you may have target creature's toughness become 1 until end of turn.

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 5 (Whenever this creature deals combat damage to a player, that player gets five poison counters.)
At the beginning of your upkeep, if an opponent is poisoned, you may destroy target Human.

Trample

When this creature enters, each player discards a card. Then return an instant or sorcery card from your graveyard to your hand.

When this creature enters, you may discard your hand. If you do, draw two cards.
Other Pirates and Rogues you control get +1/+1.
Once each turn, when you discard a card, you may create a 1/1 red Pirate creature token.

Menace
When Santriza Gang-Boss enters, it deals X damage to any target, where X is the number of Pirates and/or Rogues you control.

Whenever you cast a noncreature spell, Sara, Entelan Elementalist gets +X/+0 until end of turn, where X is Sara's power. It deals 1 damage to each creature you don't control.