Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Maximize Velocity

Target creature gets +1/+1 and gains haste until end of turn.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Reckless Charge

Target creature gets +3/+0 and gains haste until end of turn.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Accelerate

Target creature gains haste until end of turn.
Draw a card.

Assault Strobe

Target creature gains double strike until end of turn. (It deals both first-strike and regular combat damage.)

Sudden Breakthrough

Target creature gets +2/+0 and gains first strike until end of turn.
Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Downhill Charge

You may sacrifice a Mountain rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn, where X is the number of Mountains you control.

Goblin Instigator

When Goblin Instigator enters, create a 1/1 red Goblin creature token.

Bulk Up

Double target creature's power until end of turn.
Flashback {4}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)