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.)

Pestilence

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.
{B}: Pestilence deals 1 damage to each creature and each player.

Kjeldoran Dead

When Kjeldoran Dead enters, sacrifice a creature.
{B}: Regenerate Kjeldoran Dead.

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.)

Terror

Destroy target nonartifact, nonblack creature. It can't be regenerated.

Withering Wisps

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Withering Wisps.
{B}: Withering Wisps deals 1 damage to each creature and each player. Activate no more times each turn than the number of snow Swamps you control.