First strike

Soulsurge Elemental's power is equal to the number of creatures you control.

At the beginning of combat on your turn, choose any number of target planeswalkers you control. Until end of turn, they become 3/3 blue Bird creatures with flying, hexproof, and "Whenever this creature deals combat damage to a player, scry 1." (They're no longer planeswalkers. Loyalty abilities can still be activated.)

Flying, trample

Spellheart Chimera's power is equal to the number of instant and sorcery cards in your graveyard.

Spike Breeder enters with three +1/+1 counters on it.

, Remove a +1/+1 counter from Spike Breeder: Put a +1/+1 counter on target creature.

, Remove a +1/+1 counter from Spike Breeder: Create a 1/1 green Spike creature token.

Spike Colony enters with four +1/+1 counters on it.

, Remove a +1/+1 counter from Spike Colony: Put a +1/+1 counter on target creature.

Spike Feeder enters with two +1/+1 counters on it.

, Remove a +1/+1 counter from Spike Feeder: Put a +1/+1 counter on target creature.

Remove a +1/+1 counter from Spike Feeder: You gain 2 life.

Spike Rogue enters with two +1/+1 counters on it.

, Remove a +1/+1 counter from Spike Rogue: Put a +1/+1 counter on target creature.

, Remove a +1/+1 counter from a creature you control: Put a +1/+1 counter on Spike Rogue.

Spike Tiller enters with three +1/+1 counters on it.

, Remove a +1/+1 counter from Spike Tiller: Put a +1/+1 counter on target creature.

, Remove a +1/+1 counter from Spike Tiller: Target land becomes a 2/2 creature that's still a land. Put a +1/+1 counter on it.

Spike Worker enters with two +1/+1 counters on it.

, Remove a +1/+1 counter from Spike Worker: Put a +1/+1 counter on target creature.

: Regenerate Spiny Starfish.

At the beginning of each end step, if Spiny Starfish regenerated this turn, create a 0/1 blue Starfish creature token for each time it regenerated this turn.

Deathtouch

Spiteful Squad enters with two +1/+1 counters on it.

When Spiteful Squad dies, put its counters on target creature you control.

Trample

Splinterfright's power and toughness are each equal to the number of creature cards in your graveyard.

At the beginning of your upkeep, mill two cards.

Graft 2 (This creature enters with two +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)

: Regenerate target creature with a +1/+1 counter on it.

Defender (This creature can't attack.)

Whenever Sprouting Phytohydra is dealt damage, you may create a token that's a copy of Sprouting Phytohydra.

Stag Beetle enters with X +1/+1 counters on it, where X is the number of other creatures on the battlefield.

Star Pupil enters with a +1/+1 counter on it.

When Star Pupil dies, put its counters on target creature you control.

Defender (This creature can't attack.)

Landfall — Whenever a land you control enters, Steppe Lynx gets +2/+2 until end of turn.

Stingmoggie enters with two +1/+1 counters on it.

, Remove a +1/+1 counter from Stingmoggie: Destroy target artifact or land.

Reach, trample, protection from multicolored

Stonecoil Serpent enters with X +1/+1 counters on it.

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.)

This creature assigns combat damage equal to its toughness rather than its power.

Flash

You may have Stunt Double enter as a copy of any creature on the battlefield.

Sumala Rumblers's power is equal to the number of creatures you control.

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Flying, vigilance, haste

Sunbird Effigy's power and toughness are each equal to the number of colors among the exiled cards used to craft it.

: For each color among the exiled cards used to craft Sunbird Effigy, add one mana of that color.

When Sunshower Druid enters, put a +1/+1 counter on target creature and you gain 1 life.

Suq'Ata Firewalker can't be the target of red spells or abilities from red sources.

: Suq'Ata Firewalker deals 1 damage to any target.

Defender

, : Target creature can't be blocked this turn.

Trample

As Sutured Ghoul enters, exile any number of creature cards from your graveyard.

Sutured Ghoul's power is equal to the total power of the exiled cards and its toughness is equal to their total toughness.

Flying

Swarm of Bloodflies enters with two +1/+1 counters on it.

Whenever another creature dies, put a +1/+1 counter on Swarm of Bloodflies.

Swarm Shambler enters with a +1/+1 counter on it.

Whenever a creature you control with a +1/+1 counter on it becomes the target of a spell an opponent controls, create a 1/1 green Insect creature token.

, : Put a +1/+1 counter on Swarm Shambler.

Defender, hexproof

: Add one mana of any color.

Flying

Magecraft — Whenever you cast or copy an instant or sorcery spell, target creature you control has base power 2 until end of turn.

Syr Elenora, the Discerning's power is equal to the number of cards in your hand.

When Syr Elenora enters, draw a card.

Spells your opponents cast that target Syr Elenora cost more to cast.

Flying

: Talonrend gets +1/-1 until end of turn.

Tarmogoyf's power is equal to the number of card types among cards in all graveyards and its toughness is equal to that number plus 1.

All creatures able to block Taunting Elf do so.

Flying

Tempest Djinn gets +1/+0 for each basic Island you control.

Whenever Terra Ravager attacks, it gets +X/+0 until end of turn, where X is the number of lands defending player controls.

Domain — Territorial Kavu's power and toughness are each equal to the number of basic land types among lands you control.

Whenever Territorial Kavu attacks, choose one —

• Discard a card. If you do, draw a card.

• Exile up to one target card from a graveyard.

Ravenous (This creature enters with X +1/+1 counters on it. If X is 5 or more, draw a card when it enters.)

Trample

Spawn Termagants — Whenever Tervigon deals combat damage to a player, create that many 1/1 green Tyranid creature tokens.

Defender

At the beginning of your upkeep, put a spore counter on Thallid Shell-Dweller.

Remove three spore counters from Thallid Shell-Dweller: Create a 1/1 green Saproling creature token.

Whenever a player draws their second card during their turn, you draw a card.

Whenever a player casts their second spell during their turn, you create a 2/2 white Knight creature token.

Body Thief — When you cast this spell, you may exile a creature you control and put a takeover counter on it.

You may have The Master, Formed Anew enter as a copy of a creature card in exile with a takeover counter on it.

Trample

The Mycotyrant's power and toughness are each equal to the number of creatures you control that are Fungi and/or Saprolings.

At the beginning of your end step, create X 1/1 black Fungus creature tokens with "This creature can't block," where X is the number of times you descended this turn. (You descend each time a permanent card is put into your graveyard from anywhere.)

Defender

: Thermo-Alchemist deals 1 damage to each opponent.

Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Defender

Thing in the Ice enters with four ice counters on it.

Whenever you cast an instant or sorcery spell, remove an ice counter from Thing in the Ice. Then if it has no ice counters on it, transform it.

Threefold Thunderhulk enters with three +1/+1 counters on it.

Whenever Threefold Thunderhulk enters or attacks, create a number of 1/1 colorless Gnome artifact creature tokens equal to its power.

, Sacrifice another artifact: Put a +1/+1 counter on Threefold Thunderhulk.

Devour X, where X is the number of creatures devoured this way (As this enters, you may sacrifice any number of creatures. This creature enters with X +1/+1 counters on it for each of those creatures.)

Defender (This creature can't attack.)

Flying

: Thunder Wall gets +1/+1 until end of turn.

Tidewalker enters with a time counter on it for each Island you control.

Vanishing (At the beginning of your upkeep, remove a time counter from this creature. When the last is removed, sacrifice it.)

Tidewalker's power and toughness are each equal to the number of time counters on it.