Ghalta, Primal Hunger

This spell costs {X} less to cast, where X is the total power of creatures you control.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Forest

Garruk's Packleader

Whenever another creature you control with power 3 or greater enters, you may draw a card.

Colossal Dreadmaw

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Territorial Allosaurus

Kicker {2}{G} (You may pay an additional {2}{G} as you cast this spell.)
When Territorial Allosaurus enters, if it was kicked, it fights another target creature.

Ilysian Caryatid

{T}: Add one mana of any color. If you control a creature with power 4 or greater, add two mana of any one color instead.

Scrapshooter

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, when it enters, they draw a card.)
Reach
When Scrapshooter enters, if the gift was promised, destroy target artifact or enchantment an opponent controls.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Whisperer of the Wilds

{T}: Add {G}.
Ferocious — {T}: Add {G}{G}. Activate only if you control a creature with power 4 or greater.

Poison Dart Frog

Reach
{T}: Add one mana of any color.
{2}: Poison Dart Frog gains deathtouch until end of turn.