When Sinuous Benthisaur enters the battlefield, look at the top X cards of your library, where X is the number of Caves you control plus the number of Cave cards in your graveyard. Put two of those cards into your hand and the rest on the bottom of your library in a random order.

: Sinuous Striker gets +1/-1 until end of turn.

Eternalize—, Discard a card. (, Discard a card, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Snake Warrior with no mana cost. Eternalize only as a sorcery.)

When Siona, Captain of the Pyleas enters the battlefield, look at the top seven cards of your library. You may reveal an Aura card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Whenever an Aura you control becomes attached to a creature you control, create a 1/1 white Human Soldier creature token.

At the beginning of each end step, each player discards their hand.

Flying

Whenever you cast a Spirit or Arcane spell, you may draw a card.

Flying

Tribute 3 (As this creature enters the battlefield, an opponent of your choice may put three +1/+1 counters on it.)

When Siren of the Fanged Coast enters the battlefield, if tribute wasn't paid, gain control of target creature.

Raid — This spell costs less to cast if you attacked this turn.

Flying

Sisay, Weatherlight Captain gets +1/+1 for each color among other legendary permanents you control.

: Search your library for a legendary permanent card with mana value less than Sisay's power, put that card onto the battlefield, then shuffle.

Flash

Psychic Abomination — When Sister of Silence enters the battlefield, counter target instant spell, sorcery spell, activated ability, or triggered ability.

Sisterhood of Karn enters the battlefield with a +1/+1 counter on it.

Paradox — Whenever you cast a spell from anywhere other than your hand, double the number of +1/+1 counters on Sisterhood of Karn.

: Add .

, Sacrifice another creature or an artifact: For each opponent, you mill a card, then return that card from your graveyard to your hand unless that player pays 3 life. (To mill a card, put the top card of your library into your graveyard.)

Choose a Background (You can have a Background as a second commander.)

As Six-y Beast enters the battlefield, you secretly put six or fewer +1/+1 counters on it, then an opponent guesses the number of counters. If that player guesses right, sacrifice Six-y Beast after it enters the battlefield.

As an additional cost to cast this spell, exile two creature cards from your graveyard.

Trample

Tap three untapped creatures you control: Tap target creature.

Whenever Skanos Dragonheart attacks, it gets +X/+X until end of turn, where X is the greatest power among other Dragons you control and Dragon cards in your graveyard.

Choose a Background (You can have a Background as a second commander.)

: Creatures you control gain trample until end of turn.

: Target land you control becomes a 4/4 Elemental creature until end of turn. It's still a land.

Riot (This creature enters the battlefield with your choice of a +1/+1 counter or haste.)

Flying

: Skarrgan Hellkite deals 2 damage divided as you choose among one or two targets. Activate only if Skarrgan Hellkite has a +1/+1 counter on it.

Bloodthirst 3 (If an opponent was dealt damage this turn, this creature enters the battlefield with three +1/+1 counters on it.)

, Sacrifice Skarrgan Skybreaker: It deals damage equal to its power to any target.

Changeling (This card is every creature type.)

: Regenerate Skeletal Changeling.

Flying

, Sacrifice a creature: Regenerate Skeletal Kathari.

Flying

When Skeletal Vampire enters the battlefield, create two 1/1 black Bat creature tokens with flying.

, Sacrifice a Bat: Create two 1/1 black Bat creature tokens with flying.

Sacrifice a Bat: Regenerate Skeletal Vampire.

When Skeleton Archer enters the battlefield, it deals 1 damage to any target.

Skeleton Scavengers enters the battlefield with a +1/+1 counter on it.

Pay for each +1/+1 counter on Skeleton Scavengers: Regenerate Skeleton Scavengers. When it regenerates this way, put a +1/+1 counter on it.

Whenever another nontoken Elf or Berserker you control dies, you draw a card and you lose 1 life.

Reach

Whenever Skewer Slinger blocks or becomes blocked by a creature, Skewer Slinger deals 1 damage to that creature.

When Skilled Animator enters the battlefield, target artifact you control becomes an artifact creature with base power and toughness 5/5 for as long as Skilled Animator remains on the battlefield.

Bloodrush — , Discard Skinbrand Goblin: Target attacking creature gets +2/+1 until end of turn.

: Choose one. Activate only once each turn.

• Until end of turn, Skinshifter becomes a Rhino with base power and toughness 4/4 and gains trample.

• Until end of turn, Skinshifter becomes a Bird with base power and toughness 2/2 and gains flying.

• Until end of turn, Skinshifter becomes a Plant with base power and toughness 0/8.

Flying

Discard a card: Add .

Whenever Skirk Commando deals combat damage to a player, you may have it deal 2 damage to target creature that player controls.

Morph (You may cast this card face down as a 2/2 creature for . Turn it face up any time for its morph cost.)

Protection from red

Tap five untapped Goblins you control: Skirk Fire Marshal deals 10 damage to each creature and each player.

As long as you control a Beast, Skirk Outrider gets +2/+2 and has trample.

, , Discard a card: Create a 1/1 black Zombie Goblin creature token named Festering Goblin. It has "When Festering Goblin dies, target creature gets -1/-1 until end of turn."

Morph—Sacrifice two Mountains. (You may cast this card face down as a 2/2 creature for . Turn it face up any time for its morph cost.)

When Skirk Volcanist is turned face up, it deals 3 damage divided as you choose among one, two, or three target creatures.

, , Sacrifice a Human: Destroy target creature.

, , Discard a card: Each player loses 2 life.

: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)

Trample, haste

When Skitterbeam Battalion enters the battlefield, if you cast it, create two tokens that are copies of it.

//PRT-Prototype_Mech//

Prototype (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)

2/2

: Monstrosity 4. (If this creature isn't monstrous, put four +1/+1 counters on it and it becomes monstrous.)

As long as Skittering Crustacean is monstrous, it has hexproof. (It can't be the target of spells or abilities your opponents control.)

When you cast a creature spell, sacrifice Skittering Horror.

Devoid (This card has no color.)

Menace

Whenever you sacrifice a nontoken permanent, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add ."

When Skittering Surveyor enters the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Skittish Kavu gets +1/+1 as long as no opponent controls a white or blue creature.

Kicker (You may pay an additional as you cast this spell.)

Trample, haste

At the beginning of the end step, if Skizzik wasn't kicked, sacrifice it.

When Skoa, Embermage enters the battlefield, it deals 4 damage to any target.

Grandeur — Discard another card named Skoa, Embermage, Sacrifice two Mountains: Skoa deals 4 damage to any target.

: Skophos Maze-Warden gets +1/-1 until end of turn.

Whenever another creature becomes the target of an ability of a land you control named Labyrinth of Skophos, you may have Skophos Maze-Warden fight that creature. (Each deals damage equal to its power to the other.)

, Sacrifice another creature or an enchantment: Skophos Warleader gets +1/+0 and gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Menace

Command Protocols — Other artifact creatures you control get +1/+0 and have menace.

Unearth (: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

When Skulking Fugitive becomes the target of a spell or ability, sacrifice it.