Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Samut's Sprint

Target creature gets +2/+1 and gains haste until end of turn. Scry 1.

Mountain

Giant Growth

Target creature gets +3/+3 until end of turn.

Forest

Zhur-Taa Goblin

Riot (This creature enters with your choice of a +1/+1 counter or haste.)

Colossus

Target creature gets +4/+2 and gains trample until end of turn.

Collision

Collision deals 6 damage to target creature with flying.

Collision // Colossus

Rootbound Crag

Rootbound Crag enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Gruul Spellbreaker

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Trample
During your turn, you and Gruul Spellbreaker have hexproof.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Shock

Stomping Ground

({T}: Add {R} or {G}.)
As Stomping Ground enters, you may pay 2 life. If you don't, it enters tapped.

Ghitu Lavarunner

As long as there are two or more instant and/or sorcery cards in your graveyard, Ghitu Lavarunner gets +1/+0 and has haste.

Viashino Pyromancer

When Viashino Pyromancer enters, it deals 2 damage to target player or planeswalker.