When Self-Assembler enters, you may search your library for an Assembly-Worker creature card, reveal it, put it into your hand, then shuffle.

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

Whenever a Samurai or Warrior you control attacks alone, it gains lifelink until end of turn.

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

When Selkie Hedge-Mage enters, if you control two or more Forests, you may gain 3 life.

When Selkie Hedge-Mage enters, if you control two or more Islands, you may return target tapped creature to its owner's hand.

Parley — : Each player reveals the top card of their library. For each nonland card revealed this way, add and you gain 1 life. Then each player draws a card.

Parley — Each player reveals the top card of their library. For each nonland card revealed this way, you create a 3/3 green Elephant creature token. Then each player draws a card.

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.

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

When Senate Griffin enters, scry 1.

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

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

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.

Enchant creature

Enchanted creature gets +2/+2.

Madness (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

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

At the beginning of combat on each opponent's turn, tap target creature that player controls.

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.)

Flash

Enchant creature

Enchanted creature gets +1/+2 and has vigilance.

Addendum — When Sentinel's Mark enters, if you cast it during your main phase, enchanted creature gains lifelink until end of turn.

Defender

At the beginning of combat on your turn, you may clash with an opponent. If you win, Sentry Oak gets +2/+0 and loses defender until end of turn. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

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.)

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

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.)

Whenever Serene Master blocks, exchange its power and the power of target creature it's blocking until end of combat.

Whenever you gain life, you may pay . If you do, put a +1/+1 counter on target creature.

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

When Sergeant-at-Arms enters, if it was kicked, create two 1/1 white Soldier creature tokens.

, : 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.

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.)

Whenever an Elf you control dies, exile it.

, Pay 2 life: Until end of turn, you may cast a creature spell from among cards exiled with Serpent's Soul-Jar.

Flying, vigilance

Serra Avatar's power and toughness are each equal to your life total.

When Serra Avatar is put into a graveyard from anywhere, shuffle it into its owner's library.

Creatures with flying get +1/+1.

Flying, first strike

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

Whenever Serra Inquisitors blocks or becomes blocked by one or more black creatures, Serra Inquisitors gets +2/+0 until end of turn.

Flying

Once during each of your turns, you may play a land from your graveyard or cast a permanent spell with mana value 3 or less from your graveyard. If you do, it gains "When this permanent is put into a graveyard from the battlefield, exile it and you gain 2 life."

Flying, vigilance

First strike

Enchant creature

Enchanted creature gets +1/+2 as long as it's white. Otherwise, it gets -2/-1.

Flying

As Serra's Emissary enters, choose a card type.

You and creatures you control have protection from the chosen card type.

At the beginning of your upkeep, you may put a verse counter on Serra's Hymn.

Sacrifice Serra's Hymn: Prevent the next X damage that would be dealt this turn to any number of targets, divided as you choose, where X is the number of verse counters on Serra's Hymn.

: Add for each enchantment you control.

: Put a -1/-1 counter on Serrated Biskelion and a -1/-1 counter on target creature.

Flying

When Serum Raker dies, each player discards a card.

Whenever Serum Tank or another artifact enters, put a charge counter on Serum Tank.

, , Remove a charge counter from Serum Tank: Draw a card.

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.