Gruul War Chant

Attacking creatures you control get +1/+0 and have menace.

Skarrg Goliath

Trample
Bloodrush — {5}{G}{G}, Discard this card: Target attacking creature gets +9/+9 and gains trample until end of turn.

Skarrg Guildmage

{R}{G}: Creatures you control gain trample until end of turn.
{1}{R}{G}: Target land you control becomes a 4/4 Elemental creature until end of turn. It's still a land.

Elvish Mystic

Doubling Chant

For each creature you control, you may search your library for a creature card with the same name as that creature. Put those cards onto the battlefield, then shuffle.

Rubblehulk

Rubblehulk's power and toughness are each equal to the number of lands you control.
Bloodrush — {1}{R}{G}, Discard this card: Target attacking creature gets +X/+X until end of turn, where X is the number of lands you control.

Ruric Thar, the Unbowed

Vigilance, reach
Ruric Thar attacks each combat if able.
Whenever a player casts a noncreature spell, Ruric Thar deals 6 damage to that player.

Hedron Matrix

Equipped creature gets +X/+X, where X is its mana value.
Equip {4}

Forest

Fireshrieker

Equipped creature has double strike. (It deals both first-strike and regular combat damage.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Zhur-Taa Druid

{T}: Add {G}.
Whenever you tap this creature for mana, it deals 1 damage to each opponent.

Predator's Rapport

Choose target creature you control. You gain life equal to that creature's power plus its toughness.

Accorder's Shield

Equipped creature gets +0/+3 and has vigilance. (Attacking doesn't cause it to tap.)
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Dangerous

All creatures able to block target creature this turn do so.
Fuse (You may cast one or both halves of this card from your hand.)

Armed

Target creature gets +1/+1 and gains double strike until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Armed // Dangerous

Ghor-Clan Rampager

Trample
Bloodrush — {R}{G}, Discard this card: Target attacking creature gets +4/+4 and gains trample until end of turn.

Feral Animist

{3}: This creature gets +X/+0 until end of turn, where X is its power.

Gruul Guildgate

This land enters tapped.
{T}: Add {R} or {G}.

Mountain

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.