Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Secrets of the Dead

Whenever you cast a spell from your graveyard, draw a card.

Treasonous Ogre

Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Pay 3 life: Add {R}.

Mana Geyser

Add {R} for each tapped land your opponents control.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Kess, Dissident Mage

Flying
Once during each of your turns, you may cast an instant or sorcery spell from your graveyard. If a spell cast this way would be put into your graveyard, exile it instead.

Lord of the Forsaken

Flying, trample
{B}, Sacrifice another creature: Target player mills three cards.
Pay 1 life: Add {C}. Spend this mana only to cast a spell from your graveyard.

Apex of Power

Exile the top seven cards of your library. Until end of turn, you may cast spells from among them.
If this spell was cast from your hand, add ten mana of any one color.

Pyretic Ritual

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

Bonus Round

Until end of turn, whenever a player casts an instant or sorcery spell, that player copies it and may choose new targets for the copy.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Entomb

Search your library for a card, put that card into your graveyard, then shuffle.

Irencrag Feat

Add seven {R}. You can cast only one more spell this turn.

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.