Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Terramorphic Expanse

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

Greenweaver Druid

Murasa Pyromancer

Whenever Murasa Pyromancer or another Ally you control enters, you may have Murasa Pyromancer deal damage to target creature equal to the number of Allies you control.

Overrun

Creatures you control get +3/+3 and gain trample until end of turn. (Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.)

Kazuul Warlord

Whenever Kazuul Warlord or another Ally you control enters, you may put a +1/+1 counter on each Ally creature you control.

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.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Oran-Rief Survivalist

Whenever Oran-Rief Survivalist or another Ally you control enters, you may put a +1/+1 counter on Oran-Rief Survivalist.

Tajuru Archer

Whenever Tajuru Archer or another Ally you control enters, you may have Tajuru Archer deal damage to target creature with flying equal to the number of Allies you control.

Joraga Bard

Whenever Joraga Bard or another Ally you control enters, you may have Ally creatures you control gain vigilance until end of turn.

Beast Hunt

Reveal the top three cards of your library. Put all creature cards revealed this way into your hand and the rest into your graveyard.

Forest

Giant Growth

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

Borderland Ranger

When Borderland Ranger enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Mountain

Stonework Puma

Highland Berserker

Whenever Highland Berserker or another Ally you control enters, you may have Ally creatures you control gain first strike until end of turn.

Tuktuk Grunts

Haste
Whenever Tuktuk Grunts or another Ally you control enters, you may put a +1/+1 counter on Tuktuk Grunts.

Turntimber Ranger

Whenever Turntimber Ranger or another Ally you control enters, you may create a 2/2 green Wolf creature token. If you do, put a +1/+1 counter on Turntimber Ranger.

Awakener Druid

When Awakener Druid enters, target Forest becomes a 4/5 green Treefolk creature for as long as Awakener Druid remains on the battlefield. It's still a land.