Target player can't play lands this turn.
Draw a card at the beginning of the next turn's upkeep.

Exile cards from the top of your library until you exile a nonland card. You may cast that card without paying its mana cost if the spell's mana value is less than the number of Mountains you control. If you don't cast that card this way, put it into your hand.
Flashback

As an additional cost to cast this spell, discard a card at random.
Sonic Burst deals 4 damage to any target.

As an additional cost to cast this spell, discard a card at random.
Sonic Seizure deals 3 damage to any target.

Soul Sear deals 5 damage to target creature or planeswalker. That permanent loses indestructible until end of turn.

As an additional cost to cast this spell, sacrifice all creatures you control.
Soulblast deals damage to any target equal to the total power of the sacrificed creatures.

Target creature you control deals damage equal to its power to any target.

Spark Jolt deals 1 damage to any target. Scry 1.

Spark Spray deals 1 damage to any target.
Cycling

Spawning Breath deals 1 damage to any target. Create a 0/1 colorless Eldrazi Spawn creature token. It has "Sacrifice this token: Add ."

Choose two —
• Jump Kick — Destroy target artifact.
• Dash Attack — Put two +1/+1 counters on target attacking or blocking creature you control.
• Foot Toss — Target creature you control deals damage equal to its power to any other target. Then sacrifice it.

Kicker
When you cast your next instant or sorcery spell this turn, conjure a duplicate of that spell into your hand. If this spell wasn't kicked, discard the duplicate at the beginning of your next end step.

Spikefield Hazard deals 1 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.

Spit Flame deals 4 damage to target creature.
Whenever a Dragon you control enters, you may pay . If you do, return this card from your graveyard to your hand.

Spreading Flames deals 6 damage divided as you choose among any number of target creatures.

This spell costs less to cast if you control a Giant.
Squash deals 6 damage to target creature or planeswalker.

Staggershock deals 2 damage to any target.
Rebound

Starfall deals 3 damage to target creature. If that creature is an enchantment, Starfall deals 3 damage to that creature's controller.

Roll a six-sided die. Assemble a number of Contraptions equal to the result. (To assemble a Contraption, put the top card of your Contraption deck face up onto one of your sprockets.)

Convoke
Stoke the Flames deals 4 damage to any target.

Target creature gets +3/+1 until end of turn. If it's your turn, that creature gains trample until end of turn. Otherwise, it gains first strike until end of turn.

Damage can't be prevented this turn. Stomp deals 2 damage to any target. (Then exile this card. You may cast the creature later from exile.)

This spell costs less to cast for each attacking creature.
Create a 6/12 colorless Construct artifact creature token with trample. Exile it at the beginning of your next end step.

Stonefury deals damage to target creature equal to the number of lands you control.

Target creature gets +1/+0 and gains first strike until end of turn. Scry 1.

Switch target creature's power and toughness until end of turn.
Splice onto Arcane

Target creature can't block this turn.
Draw a card.

Target creature gets +2/+0 and gains first strike until end of turn.
Create a Treasure token.

Sudden Impact deals damage to target player equal to the number of cards in that player's hand.

Split second
Sudden Shock deals 2 damage to any target.