Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Lightning Skelemental

Trample, haste
Whenever Lightning Skelemental deals combat damage to a player, that player discards two cards.
At the beginning of the end step, sacrifice Lightning Skelemental.

Arc Runner

Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice Arc Runner.

Ziatora, the Incinerator

Flying
At the beginning of your end step, you may sacrifice another creature. When you do, Ziatora, the Incinerator deals damage equal to that creature's power to any target and you create three Treasure tokens.

Phyrexian Soulgorger

Cumulative upkeep—Sacrifice a creature. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Groundbreaker

Trample, haste
At the beginning of the end step, sacrifice Groundbreaker.

Crumbling Colossus

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When Crumbling Colossus attacks, sacrifice it at end of combat.