Lava Dart

Lava Dart deals 1 damage to any target.
Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Ancient Imperiosaur

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Trample, ward {2}
Ancient Imperiosaur enters with two +1/+1 counters on it for each creature that convoked it.

Burning-Tree Emissary

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

Halo Hopper

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)

Mishra's Bauble

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Hidden Herbalists

Revolt — When Hidden Herbalists enters, if a permanent you controlled left the battlefield this turn, add {G}{G}.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Thrasta, Tempest's Roar

This spell costs {3} less to cast for each other spell cast this turn.
Trample, haste
Trample over planeswalkers (This creature can deal excess combat damage to the controller of the planeswalker it's attacking.)
Thrasta, Tempest's Roar has hexproof as long as it entered this turn.

Frogmite

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Mutagenic Growth

({G/P} can be paid with either {G} or 2 life.)
Target creature gets +2/+2 until end of turn.