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

Flying

Whenever Scythe Specter deals combat damage to a player, each opponent discards a card. Each player who discarded a card with the highest mana value among cards discarded this way loses life equal to that mana value.

Sea Serpent can't attack unless defending player controls an Island.

When you control no Islands, sacrifice Sea Serpent.

Flying, protection from red

Sacrifice Seal of Primordium: Destroy target artifact or enchantment.

This spell costs less to cast for each creature you attacked with this turn.

When Search Party Captain enters, draw a card.

Flying

When Searchlight Companion enters, create a 1/1 colorless Spirit creature token.

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)

: Searing Spear Askari gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Whenever Seascape Aerialist or another Ally you control enters, you may have Ally creatures you control gain flying until end of turn.

Tasty (This creature can be attacked directly. If it is attacked, it can't block creatures that didn't attack it.)

Enchant creature or planeswalker you don't control

When Seatower Imprisonment enters the battlefield, conjure a card named Soldiers of the Watch onto the battlefield.

Enchanted permanent can't attack or block, and its activated abilities can't be activated.

Nonland permanents you control and permanent spells you control are enchantments in addition to their other types.

(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Face-down creatures you control get +0/+1.

Whenever a permanent you control is turned face up, draw a card.

Enchant creature

As long as enchanted creature is attacking alone, it can't be blocked.

Enchanted creature has "Whenever this creature deals combat damage to a player, it connives." (Its controller draws a card, then discards a card. If they discarded a nonland card, they put a +1/+1 counter on this creature.)

Flying

Whenever Sedraxis Specter deals combat damage to a player, that player discards a card.

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.)

Destroy target artifact or enchantment. If was spent to cast this spell, create two 1/1 green Saproling creature tokens.

Flying

Whenever Seedpod Squire attacks, target creature you control without flying gets +1/+1 until end of turn.

: Add .

, Sacrifice Seething Landscape: Search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Cycling (, Discard this card: Draw a card.)

Seismic Rupture deals 2 damage to each creature without flying.

Creatures without flying can't block this turn.

As an additional cost to cast this spell, discard a card.

Draw two cards and create a Treasure token. (It's an artifact with ", Sacrifice this artifact: Add one mana of any color.")

Sejiri Steppe enters tapped.

When Sejiri Steppe enters, target creature you control gains protection from the color of your choice until end of turn.

: Add .

Return target tapped creature to its owner's hand. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Search your library for a basic land card and reveal it. If there's a tree in its art, put it onto the battlefield tapped. Otherwise, put it into your hand. Then shuffle.

Flying

Sacrifice Selfless Spirit: Creatures you control gain indestructible until end of turn.

Council's dilemma — Starting with you, each player votes for wild or free. Reveal cards from the top of your library until you reveal a creature card for each wild vote. Put those creature cards onto the battlefield, then shuffle the rest into your library. You may put a permanent card from your hand onto the battlefield for each free vote.

Artifacts you control are Clues in addition to their other types and have ", Sacrifice this artifact: Draw a card."

Whenever you sacrifice a Clue, target creature can't be blocked this turn.

Flying (This creature can't be blocked except by creatures with flying or reach.)

Whenever a creature dealt damage by Sengir Vampire this turn dies, put a +1/+1 counter on Sengir Vampire.

When Sensor Splicer enters, create a 3/3 colorless Phyrexian Golem artifact creature token.

Golem creatures you control have vigilance.

Flash

When Sentinel of the Pearl Trident enters, you may exile target historic permanent you control. If you do, return that card to the battlefield under its owner's control at the beginning of the next end step. (Artifacts, legendaries, and Sagas are historic.)

Flying, vigilance

, Exile Senu, Keen-Eyed Protector: You gain 2 life and scry 2.

When a legendary creature you control attacks and isn't blocked, if Senu is exiled, put it onto the battlefield attacking.

You may pay and tap four untapped creatures you control with flying rather than pay this spell's mana cost.

Flying, lifelink

Other creatures you control with flying have indestructible. (Damage and effects that say "destroy" don't destroy them.)

Sacrifice another creature: Sepulcher Ghoul gets +2/+2 until end of turn. Activate only once each turn.

Flying

Whenever a creature dealt damage by Seraph this turn dies, put that card onto the battlefield under your control at the beginning of the next end step. Sacrifice the creature when you lose control of Seraph.

Flying

: Transform Seraph of New Capenna. Activate only as a sorcery. ( can be paid with either or 2 life.)

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)

Flying

Seraph of the Masses's power and toughness are each equal to the number of creatures you control.

Flying

Indestructible (Damage and effects that say "destroy" don't destroy this creature. If its toughness is 0 or less, it's still put into its owner's graveyard.)

When Seraph Sanctuary enters, you gain 1 life.

Whenever an Angel you control enters, you gain 1 life.

: Add .

First strike, lifelink

Whenever Seraphic Steed attacks while saddled, create a 3/3 white Angel creature token with flying.

Saddle 4 (Tap any number of other creatures you control with total power 4 or more: This Mount becomes saddled until end of turn. Saddle only as a sorcery.)

, : Create a 1/1 colorless Snake artifact creature token. It has "Whenever this creature deals damage to a player, that player gets a poison counter." (A player with ten or more poison counters loses the game.)

Krakens, Leviathans, Octopuses, and Serpents you control can't be blocked except by Krakens, Leviathans, Octopuses, and Serpents.

When Serpent Warrior enters, you lose 3 life.

Landfall — Whenever a land you control enters,

Augment (, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)

Whenever Serpentine Basilisk deals combat damage to a creature, destroy that creature at end of combat.

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

: Serpentine Kavu gains haste until end of turn.

Target creature gains deathtouch until end of turn. (Any amount of damage it deals to a creature is enough to destroy it.)

Flying, first strike

Whenever you cast a historic spell, Serra Disciple gets +1/+1 until end of turn. (Artifacts, legendaries, and Sagas are historic.)

: Prevent the next 1 damage that would be dealt to any target this turn.

, : Target creature gains vigilance until end of turn.

Flying, vigilance

: Add .

Any time you could mulligan and Serum Powder is in your hand, you may exile all the cards from your hand, then draw that many cards. (You can do this in addition to taking mulligans.)