Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Lifelink

Kicker {B} (You may pay an additional {B} as you cast this spell.) When this creature enters, if it was kicked, target player sacrifices a creature of their choice.

As long as an opponent has 10 or less life, this creature gets +2/+1 and has intimidate. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)

Flying, protection from white When this creature enters, each opponent loses life equal to the number of Vampires you control. You gain life equal to the life lost this way.

Flying Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.) Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

This land enters tapped. When this land enters, target player loses 1 life. {T}: Add {B}.

Kicker—Tap an untapped Vampire you control. (You may tap a Vampire you control in addition to any other costs as you cast this spell.) Target opponent loses half their life, rounded up. If this spell was kicked, you gain life equal to the life lost this way.