: Regenerate Selesnya Sentry.

, Sacrifice Selfless Cathar: Creatures you control get +1/+1 until end of turn.

Exile Selfless Glyphweaver: Creatures you control gain indestructible until end of turn.

Sacrifice Selfless Savior: Another target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Flash

When Selfless Squire enters, prevent all damage that would be dealt to you this turn.

Whenever damage that would be dealt to you is prevented, put that many +1/+1 counters on Selfless Squire.

Whenever Selhoff Occultist or another creature dies, target player mills a card.

When Seller of Songbirds enters, create a 1/1 white Bird creature token with flying.

Vigilance

Whenever you cast a creature spell, create a 1/1 red Mercenary creature token with ": Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."

: Choose a color. Add one mana of that color for each different power among creatures you control.

Whenever another creature enters, its controller may draw a card if its power is greater than each other creature's power.

, : Add X mana in any combination of colors, where X is the greatest power among creatures you control.

Whenever Semblance Scanner or equipped creature deals combat damage to a player, if it's not a token, conjure a duplicate of it into your hand.

Reconfigure (: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Flying

: Senate Courier gains vigilance until end of turn.

, : You gain 2 life.

, : Draw a card, then discard a card.

When Sengir Autocrat enters, create three 0/1 black Serf creature tokens.

When Sengir Autocrat leaves the battlefield, exile all Serf tokens.

Flying

Whenever one or more other creatures die, put a +1/+1 counter on Sengir Connoisseur. This ability triggers only once each 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.

Kinship — At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with Sensation Gorger, you may reveal it. If you do, each player discards their hand, then draws four cards.

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

Golem creatures you control have vigilance.

When Sentinel of Lost Lore enters, choose one or more —

• Return target card you own in exile that has an Adventure to your hand.

• Put target card you don't own in exile that has an Adventure on the bottom of its owner's library.

• Exile target player's graveyard.

Vigilance

Whenever Sentinel of the Nameless City enters or attacks, create a Map token. (It's an artifact with ", , Sacrifice this artifact: Target creature you control explores. Activate only as a sorcery.")

Haste

As long as an artifact entered the battlefield under your control this turn, creatures you control get +2/+2.

Battalion — Whenever Sentinel Sarah Lyons and at least two other creatures attack, Sentinel Sarah Lyons deals damage equal to the number of artifacts you control to target player.

Vigilance, reach

Flash

This spell costs less to cast for each creature attacking you.

When Sentry Bot enters, you get for each creature attacking you.

At the beginning of combat on your turn, you may pay . If you do, put a +1/+1 counter on each creature you control.

Flying, vigilance

, Pay 3 life: Regenerate Sentry of the Underworld.

When Separatist Voidmage enters, you may return target creature to its owner's hand.

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Whenever Septic Rats attacks, if defending player is poisoned, it gets +1/+1 until end of turn.

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)

When Sepulchral Primordial enters, for each opponent, you may put up to one target creature card from that player's graveyard onto the battlefield under your control.

Flying, lifelink

Flying

Whenever Seraph of New Phyrexia attacks, you may sacrifice another creature or artifact. If you do, Seraph of New Phyrexia gets +2/+1 until end of turn.

Flying

: Seraph of the Scales gains vigilance until end of turn.

: Seraph of the Scales gains deathtouch until end of turn.

Afterlife 2 (When this creature dies, create two 1/1 white and black Spirit creature tokens with flying.)

Flying

Prevent all combat damage that would be dealt to Seraph of the Sword.

Flying

At the beginning of your upkeep, sacrifice a land. If you sacrifice an Island this way, Serendib Djinn deals 3 damage to you.

When you control no lands, sacrifice Serendib Djinn.

: Target creature other than Serendib Sorcerer has base power and toughness 0/2 until end of turn.

When Serene Sleuth enters, investigate. (Create a Clue token. It's an artifact with ", Sacrifice this artifact: Draw a card.")

At the beginning of combat on your turn, investigate for each goaded creature you control. Then each creature you control is no longer goaded.

Trample, haste

Share Intelligence — Whenever Sergeant John Benton deals combat damage to a player, you and that player each draw that many cards.

When Serpent Assassin enters, you may destroy target nonblack creature.

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

Backup 1 (When this creature enters, put a +1/+1 counter on target creature. If that's another creature, it gains the following ability until end of turn.)

Deathtouch

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.)

Flying

: Target attacking or blocking creature gets +2/+2 until end of turn.

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

You can't cast Serra Avenger during your first, second, or third turns of the game.

Flying, vigilance

Flying, vigilance

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

, : Target creature gains vigilance until end of turn.

Flying

Whenever another creature you control with power 2 or less enters, put two +1/+1 counters on that creature.

First strike

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

Vigilance (Attacking doesn't cause this creature to tap.)

Other creatures you control have vigilance.

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

Flying

Whenever you cast a noncreature spell, put an oil counter on Serum Sovereign.

, Remove an oil counter from Serum Sovereign: Draw a card, then scry 2.

Flying

Whenever you cast a noncreature spell, put an oil counter on Serum-Core Chimera.

Remove three oil counters from Serum-Core Chimera: Draw a card. Then you may discard a nonland card. When you discard a card this way, Serum-Core Chimera deals 3 damage to target creature or planeswalker. Activate only as a sorcery.

When Servant of the Conduit enters, you get (two energy counters).

, Pay : Add one mana of any color.