Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Smoke

Players can't untap more than one creature during their untap steps.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Spellskite

{U/P}: Change a target of target spell or ability to this creature. ({U/P} can be paid with either {U} or 2 life.)

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Tolarian Winds

Discard all the cards in your hand, then draw that many cards.

Izzet Signet

Overmaster

The next instant or sorcery spell you cast this turn can't be countered.
Draw a card.

Furnace of Rath

If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Misdirection

You may exile a blue card from your hand rather than pay this spell's mana cost.
Change the target of target spell with a single target.

Blood Moon

Repercussion

Whenever a creature is dealt damage, this enchantment deals that much damage to that creature's controller.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Meltdown

Destroy each artifact with mana value X or less.

Fault Line

Fault Line deals X damage to each creature without flying and each player.

Firestorm

As an additional cost to cast this spell, discard X cards.
Firestorm deals X damage to each of X targets.

Mogg Salvage

If an opponent controls an Island and you control a Mountain, you may cast this spell without paying its mana cost.
Destroy target artifact.

Counterspell

Sol Ring

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.