: Regenerate Selesnya Sentry.

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.

: Exile target creature card from a graveyard. That card deals damage equal to its power to Selfless Exorcist.

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.)

Flying

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

Create a token that's a copy of target creature you control.

Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Parley — When Selvala's Enforcer enters, each player reveals the top card of their library. For each nonland card revealed this way, put a +1/+1 counter on Selvala's Enforcer. Then each player draws a card.

Exile any number of target creatures and/or planeswalkers you control. At the beginning of the next end step, return each of them to the battlefield under its owner's control. Each of them enters with an additional +1/+1 counter on it if it's a creature and an additional loyalty counter on it if it's a planeswalker.

Flying

: Senate Courier gains vigilance until end of turn.

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

, Exile Sengir Nosferatu: Create a 1/2 black Bat creature token with flying. It has ", Sacrifice this creature: Return an exiled card named Sengir Nosferatu to the battlefield under its owner's control."

Flying

Whenever another creature dies, put two +1/+1 counters on Sengir, the Dark Baron.

Whenever another player loses the game, you gain life equal to that player's life total as the turn began.

Partner (You can have two commanders if both have partner.)

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.)

Enchant creature

Enchanted creature gets -3/-0.

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.

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

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.

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

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.)

Flying

At the beginning of your upkeep, Serendib Efreet deals 1 damage to you.

Destroy all Auras.

Destroy target enchantment. You gain life equal to its mana value.

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.

Prevent all combat damage X target creatures would deal this turn.

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.

Serpent of the Endless Sea's power and toughness are each equal to the number of Islands you control.

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

Flash

Enchant creature

Enchanted creature gets +1/+1.

: Regenerate enchanted creature.

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

Until end of turn, target creature becomes a blue Serpent with base power and toughness 5/5.

Create a 0/0 green and blue Fractal creature token. Put X +1/+1 counters on it, where X is one plus the total number of instant and sorcery cards you own in exile and in your graveyard.

Devoid (This card has no color.)

Serpentine Spike deals 2 damage to target creature, 3 damage to another target creature, and 4 damage to a third target creature. If a creature dealt damage this way would die this turn, exile it instead.

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

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.