Feebleness

Flash
Enchant creature
Enchanted creature gets -2/-1.

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek the Merciless deals damage equal to that spell's mana value to any target.

Jhoira's Timebug

{T}: Choose target permanent you control or suspended card you own. If that permanent or card has a time counter on it, you may remove a time counter from it or put another time counter on it.

Needlepeak Spider

Trespasser il-Vec

Discard a card: Trespasser il-Vec gains shadow until end of turn. (It can block or be blocked by only creatures with shadow.)

Bedlam Reveler

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Prowess
When Bedlam Reveler enters, discard your hand, then draw three cards.

Blightspeaker

{T}: Target player loses 1 life.
{4}, {T}: Search your library for a Rebel permanent card with mana value 3 or less, put it onto the battlefield, then shuffle.

Reiterate

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Copy target instant or sorcery spell. You may choose new targets for the copy.

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Cloud Key

As Cloud Key enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Assassinate

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Arc Blade

Arc Blade deals 2 damage to any target. Exile Arc Blade with three time counters on it.
Suspend 3—{2}{R} (Rather than cast this card from your hand, you may pay {2}{R} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Minions' Murmurs

You draw X cards and you lose X life, where X is the number of creatures you control.

Mountain

Swamp

Skirk Shaman

Skirk Shaman can't be blocked except by artifact creatures and/or red creatures.

Grapeshot

Grapeshot deals 1 damage to any target.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Coal Stoker

When Coal Stoker enters, if you cast it from your hand, add {R}{R}{R}.

Molten Rain

Destroy target land. If that land was nonbasic, Molten Rain deals 2 damage to the land's controller.

Gorgon Recluse

Whenever Gorgon Recluse blocks or becomes blocked by a nonblack creature, destroy that creature at end of combat.
Madness {B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Deadly Grub

Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Deadly Grub dies, if it had no time counters on it, create a 6/1 green Insect creature token with shroud. (It can't be the target of spells or abilities.)

Street Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Cycling—Pay 2 life. (Pay 2 life, Discard this card: Draw a card.)

Haze of Rage

Buyback {2} (You may pay an additional {2} as you cast this spell. If you do, put this card into your hand as it resolves.)
Creatures you control get +1/+0 until end of turn.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)