Instigator

{1}{B}{B}, {T}, Discard a card: Creatures target player controls attack this turn if able.

Goblin Diplomats

{T}: Each creature attacks this turn if able.

Shattergang Brothers

{2}{B}, Sacrifice a creature: Each other player sacrifices a creature.
{2}{R}, Sacrifice an artifact: Each other player sacrifices an artifact.
{2}{G}, Sacrifice an enchantment: Each other player sacrifices an enchantment.

Chaosphere

Creatures with flying can block only creatures with flying.
Creatures without flying have reach. (They can block creatures with flying.)