Sea Serpent

Sea Serpent can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Sea Serpent.

Plague Rats

Plague Rats's power and toughness are each equal to the number of creatures named Plague Rats on the battlefield.

Prodigal Sorcerer

{T}: Prodigal Sorcerer deals 1 damage to any target.

Psychic Venom

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

Howl from Beyond

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

Scavenging Ghoul

At the beginning of each end step, put a corpse counter on Scavenging Ghoul for each creature that died this turn.
Remove a corpse counter from Scavenging Ghoul: Regenerate Scavenging Ghoul.

Lord of the Pit

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Lord of the Pit. If you can't, Lord of the Pit deals 7 damage to you.

Swamp

Dark Ritual

Ancestral Recall

Spell Blast

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

Demonic Tutor

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

Flying Men

Unsummon

Return target creature to its owner's hand.

Drudge Skeletons

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

Mox Sapphire

Island

Raise Dead

Return target creature card from your graveyard to your hand.

Cursed Land

Enchant land
At the beginning of the upkeep of enchanted land's controller, Cursed Land deals 1 damage to that player.

Weakness

Enchant creature
Enchanted creature gets -2/-1.

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Frozen Shade

{B}: Frozen Shade gets +1/+1 until end of turn.

Glasses of Urza

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.)