Goblin Grenade

As an additional cost to cast this spell, sacrifice a Goblin.
Goblin Grenade deals 5 damage to any target.

Grapeshot Catapult

{T}: Grapeshot Catapult deals 1 damage to target creature with flying.

Mountain

Giant Growth

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

Goblin War Drums

Creatures you control have menace. (They can't be blocked except by two or more creatures.)

Goblin Balloon Brigade

{R}: Goblin Balloon Brigade gains flying until end of turn.

Gauntlets of Chaos

{5}, Sacrifice Gauntlets of Chaos: Exchange control of target artifact, creature, or land you control and target permanent an opponent controls that shares one of those types with it. If those permanents are exchanged this way, destroy all Auras attached to them.

Giant Spider

Reach (This creature can block creatures with flying.)

Giant Strength

Enchant creature
Enchanted creature gets +2/+2.

Giant Turtle

Giant Turtle can't attack if it attacked during your last turn.

Goblin Chirurgeon

Sacrifice a Goblin: Regenerate target creature.

Forest

Jalum Tome

{2}, {T}: Draw a card, then discard a card.

Granite Gargoyle

Flying
{R}: Granite Gargoyle gets +0/+1 until end of turn.