Ogre Battledriver

Whenever another creature you control enters, that creature gets +2/+0 and gains haste until end of turn. (It can attack and {T} this turn.)

Lathliss, Dragon Queen

Flying
Whenever another nontoken Dragon you control enters, create a 5/5 red Dragon creature token with flying.
{1}{R}: Dragons you control get +1/+0 until end of turn.

Flame-Blessed Bolt

Flame-Blessed Bolt deals 2 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

Utvara Hellkite

Flying
Whenever a Dragon you control attacks, create a 6/6 red Dragon creature token with flying.

Stormwing Dragon

Flying, first strike
Megamorph {5}{R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Stormwing Dragon is turned face up, put a +1/+1 counter on each other Dragon creature you control.

Siege Dragon

Flying
When Siege Dragon enters, destroy all Walls your opponents control.
Whenever Siege Dragon attacks, if defending player controls no Walls, it deals 2 damage to each creature without flying that player controls.

Storm Strike

Target creature gets +1/+0 and gains first strike until end of turn. Scry 1.

Fiery Emancipation

If a source you control would deal damage to a permanent or player, it deals triple that damage to that permanent or player instead.

Drakuseth, Maw of Flames

Flying
Whenever Drakuseth, Maw of Flames attacks, it deals 4 damage to any target and 3 damage to each of up to two other targets.

Archetype of Aggression

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

Crucible of Fire

Haven of the Spirit Dragon

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a Dragon creature spell.
{2}, {T}, Sacrifice Haven of the Spirit Dragon: Return target Dragon creature card or Ugin planeswalker card from your graveyard to your hand.

Mountain

Impact Tremors

Whenever a creature you control enters, Impact Tremors deals 1 damage to each opponent.

Berserkers' Onslaught

Attacking creatures you control have double strike.

Ferocity of the Wilds

Attacking non-Human creatures you control get +1/+0 and have trample.

Sarkhan the Masterless

Whenever a creature attacks you or a planeswalker you control, each Dragon you control deals 1 damage to that creature.
+1: Until end of turn, each planeswalker you control becomes a 4/4 red Dragon creature and gains flying.
−3: Create a 4/4 red Dragon creature token with flying.

Terror of the Peaks

Flying
Spells your opponents cast that target Terror of the Peaks cost an additional 3 life to cast.
Whenever another creature you control enters, Terror of the Peaks deals damage equal to that creature's power to any target.

Ashmouth Dragon

Flying
Whenever you cast an instant or sorcery spell, Ashmouth Dragon deals 2 damage to any target.

Smoldering Egg

Defender
Whenever you cast an instant or sorcery spell, put a number of ember counters on Smoldering Egg equal to the amount of mana spent to cast that spell. Then if Smoldering Egg has seven or more ember counters on it, remove them and transform Smoldering Egg.

Smoldering Egg // Ashmouth Dragon

Dragon Tempest

Whenever a creature you control with flying enters, it gains haste until end of turn.
Whenever a Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.

Shockmaw Dragon

Flying
Whenever Shockmaw Dragon deals combat damage to a player, it deals 1 damage to each creature that player controls.

Circle of Flame

Whenever a creature without flying attacks you or a planeswalker you control, Circle of Flame deals 1 damage to that creature.