Dragon creatures you control get +3/+3.

Flying, trample Megamorph {5}{G}{G} (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 Herdchaser Dragon is turned face up, put a +1/+1 counter on each other Dragon creature you control.

As Outpost Siege enters the battlefield, choose Khans or Dragons. • Khans — At the beginning of your upkeep, exile the top card of your library. Until end of turn, you may play that card. • Dragons — Whenever a creature you control leaves the battlefield, Outpost Siege deals 1 damage to any target.

Flying, trample Whenever a Dragon you control attacks, it gains double strike until end of turn.

Rugged Highlands enters the battlefield tapped. When Rugged Highlands enters the battlefield, you gain 1 life. {T}: Add {R} or {G}.

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.

As Frontier Siege enters the battlefield, choose Khans or Dragons. • Khans — At the beginning of each of your main phases, add {G}{G}. • Dragons — Whenever a creature with flying enters the battlefield under your control, you may have it fight target creature you don't control.

+1: Until end of turn, Sarkhan, the Dragonspeaker becomes a legendary 4/4 red Dragon creature with flying, indestructible, and haste. (He doesn't lose loyalty while he's not a planeswalker.) −3: Sarkhan, the Dragonspeaker deals 4 damage to target creature. −6: You get an emblem with "At the beginning of your draw step, draw two additional cards" and "At the beginning of your end step, discard your hand."

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