Spell Blast

Counter target spell with mana value X. (For example, if that spell's mana cost is {3}{U}{U}, X is 5.)

Drain Life

Spend only black mana on X.
Drain Life deals X damage to any target. You gain life equal to the damage dealt, but not more life than the player's life total before the damage was dealt, the planeswalker's loyalty before the damage was dealt, or the creature's toughness.

Unsummon

Return target creature to its owner's hand.

Psychic Venom

Enchant land
Whenever enchanted land becomes tapped, this Aura deals 2 damage to that land's controller.

Bog Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Prodigal Sorcerer

{T}: This creature deals 1 damage to any target.

Black Lotus

{T}, Sacrifice this artifact: Add three mana of any one color.

Sinkhole

Psionic Blast

Psionic Blast deals 4 damage to any target and 2 damage to you.

Dark Ritual

Air Elemental

Island

Mox Sapphire

Howl from Beyond

Target creature gets +X/+0 until end of turn.

Black Knight

First strike (This creature deals combat damage before creatures without first strike.)
Protection from white (This creature can't be blocked, targeted, dealt damage, or enchanted by anything white.)

Library of Leng

You have no maximum hand size.
If an effect causes you to discard a card, discard it, but you may put it on top of your library instead of into your graveyard.

Swamp

Drudge Skeletons

{B}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)