As an additional cost to cast this spell, sacrifice a creature.
Target creature gets -X/-X until end of turn, where X is the sacrificed creature's power.

Revolt — At the beginning of your end step, if a permanent left the battlefield under your control this turn, put a unity counter on this enchantment.
Creatures you control get +1/+1 for each unity counter on this enchantment.

Cascade, cascade
Call Forth the Tempest deals damage to each creature your opponents control equal to the total mana value of other spells you've cast this turn.

Put target creature card chosen at random from a graveyard onto the battlefield under your control. Call from the Grave deals to you damage equal to that creature's mana value.

Players can't gain life this turn. Damage can't be prevented this turn. Call In a Professional deals 3 damage to any target.

Create a 3/3 green Centaur creature token.

Return up to two target creature cards with total mana value 3 or less from your graveyard to the battlefield. Put a deathtouch counter on either of them. Then put a menace counter on either of them.

Enchant creature
Enchanted creature gets +3/+2 and has trample.
At the beginning of each upkeep, if a player cast two or more spells last turn, sacrifice this Aura.

Create a 3/3 green Elephant creature token.
Flashback

Create a 1/1 blue and black Horror creature token with flying.
Cipher

At the beginning of your upkeep, the Ring tempts you.
Whenever you choose a creature as your Ring-bearer, you may pay 2 life. If you do, draw a card.

: Reveal the top card of your library. If it's a creature card, put it onto the battlefield. Otherwise, put it into your graveyard.

, Discard a card: Create a 1/1 black Vampire Knight creature token with lifelink. Activate only once each turn.

Create two 2/2 white Knight creature tokens with vigilance.

Strive — This spell costs more to cast for each target beyond the first.
Choose any number of target opponents. Create X 1/1 white Human Soldier creature tokens, where X is the number of creatures those opponents control.

Suspend 2 —
Conjure two cards named Siege Rhino onto the battlefield.

Search your library for a planeswalker card, reveal it, put it into your hand, then shuffle.

Search your library for a Mountain card, reveal it, put it into your hand, then shuffle. Create a 2/2 green Bird creature token with "Whenever a land you control enters, this token gets +1/+0 until end of turn."
Flashback

Devoid
Create two 1/1 colorless Eldrazi Scion creature tokens. They have "Sacrifice this token: Add ."

Create a 5/5 blue and red Elemental creature token with flying.
Retrace

Dragons you control have indestructible.
At the beginning of your upkeep, for each color, put a +1/+1 counter on a Dragon you control of that color. If you put +1/+1 counters on five Dragons this way, you win the game.

As this enchantment enters, choose a color and an opponent.
White creatures get +1/+1 as long as the chosen color is the most common color among nontoken permanents the chosen player controls but isn't tied for most common.
When the chosen color isn't the most common color among nontoken permanents the chosen player controls or is tied for most common, sacrifice this enchantment.

Untap all creatures you control. Samurai creatures you control get +1/+1 until end of turn.

Return target creature to its owner's hand. Its controller draws a card.

Return target instant or sorcery card from your graveyard to your hand.

Enchant nonblack creature
Enchanted creature gets +1/+2, has flying, and is an Angel in addition to its other types.

Create three 1/1 white Vampire creature tokens with lifelink.