Spark Elemental

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

Blitz Hellion

Trample, haste
At the beginning of the end step, this creature's owner shuffles it into their library.

Jaws of Defeat

Whenever a creature you control enters, target opponent loses life equal to the difference between that creature's power and its toughness.

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.

Cactuar

Trample
At the beginning of your end step, if this creature didn't enter the battlefield this turn, return it to its owner's hand.

Berserk

Cast this spell only before the combat damage step.
Target creature gains trample and gets +X/+0 until end of turn, where X is its power. At the beginning of the next end step, destroy that creature if it attacked this turn.

Mr. Orfeo, the Boulder

Whenever you attack, double target creature's power until end of turn.

Ziatora's Proving Ground

({T}: Add {B}, {R}, or {G}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

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 this creature.

Elemental Appeal

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a 7/1 red Elemental creature token with trample and haste. Exile it at the beginning of the next end step. If this spell was kicked, that creature gets +7/+0 until end of turn.

Blistering Firecat

Trample, haste
At the beginning of the end step, sacrifice this creature.
Morph {R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Groundbreaker

Trample, haste
At the beginning of the end step, sacrifice this creature.

Lightning Skelemental

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

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Jumbo Cactuar

10,000 Needles — Whenever this creature attacks, it gets +9999/+0 until end of turn.

Akoum Stonewaker

Landfall — Whenever a land you control enters, you may pay {2}{R}. If you do, create a 3/1 red Elemental creature token with trample and haste. Exile that token at the beginning of the next end step.

Feral Lightning

Create three 3/1 red Elemental creature tokens with haste. Exile them at the beginning of the next end step.