Argivian Phalanx

This spell costs {1} less to cast for each creature you control.
Vigilance (Attacking doesn't cause this creature to tap.)

Imperiosaur

Spend only mana produced by basic lands to cast this spell.

As an additional cost to cast this spell, sacrifice a creature.
Reckless Abandon deals 4 damage to any target.

When Burning-Tree Emissary enters, add {R}{G}.

Wild Nacatl gets +1/+1 as long as you control a Mountain.
Wild Nacatl gets +1/+1 as long as you control a Plains.

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.