Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

Hero of Oxid Ridge

Haste
Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Whenever Hero of Oxid Ridge attacks, creatures with power 1 or less can't block this turn.

Goblin Chariot

Haste (This creature can attack and {T} as soon as it comes under your control.)

Goblin War Buggy

Haste
Echo {1}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Mayhem Devil

Whenever a player sacrifices a permanent, Mayhem Devil deals 1 damage to any target.

Motivated Pony

Trample, haste
Whenever Motivated Pony attacks, attacking creatures get +1/+1 until end of turn. If a Food entered under your control this turn, untap those creatures and they get an additional +2/+2 until end of turn.

Fervent Cathar

Haste
When Fervent Cathar enters, target creature can't block this turn.

Embereth Paladin

Haste
Adamant — If at least three red mana was spent to cast this spell, Embereth Paladin enters with a +1/+1 counter on it.

Fervent Champion

First strike, haste
Whenever Fervent Champion attacks, another target attacking Knight you control gets +1/+0 until end of turn.
Equip abilities you activate that target Fervent Champion cost {3} less to activate.

Éomer, Marshal of Rohan

Haste
Whenever one or more other attacking legendary creatures you control die, untap all creatures you control. After this phase, there is an additional combat phase. This ability triggers only once each turn.

Rhythm of the Wild

Creature spells you control can't be countered.
Nontoken creatures you control have riot. (They enter with your choice of a +1/+1 counter or haste.)

Blazing Specter

Flying, haste
Whenever Blazing Specter deals combat damage to a player, that player discards a card.

Ognis, the Dragon's Lash

Haste
Whenever a creature you control with haste attacks, create a tapped Treasure token.

Riders of the Mark

This spell costs {1} less to cast for each Human you control.
Trample, haste
At the beginning of your end step, if Riders of the Mark attacked this turn, return it to its owner's hand. If you do, create a number of 1/1 white Human Soldier creature tokens equal to its toughness.

Viashino Branchrider

Kicker {2}{G} (You may pay an additional {2}{G} as you cast this spell.)
Haste
If Viashino Branchrider was kicked, it enters with two +1/+1 counters on it.
{2}{R}: Viashino Branchrider gets +2/+0 until end of turn.

Valley Dasher

Haste
Valley Dasher attacks each combat if able.

Seeker of Slaanesh

Haste
Allure of Slaanesh — Each opponent must attack with at least one creature each combat if able.

Deathless Knight

Haste
When you gain life for the first time each turn, return Deathless Knight from your graveyard to your hand.

Atalan Jackal

Trample, haste
Skilled Outrider — Whenever Atalan Jackal deals combat damage to a player, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Ogre Battledriver

Whenever another creature you control enters, that creature gets +2/+0 and gains haste until end of turn. (It can attack and {T} this turn.)

Éomer of the Riddermark

Haste
Whenever Éomer of the Riddermark attacks, if you control a creature with the greatest power among creatures on the battlefield, create a 1/1 white Human Soldier creature token.