Wose Pathfinder

{T}: Add one mana of any color.
{6}{G}, {T}: Another target creature gets +3/+3 and gains trample until end of turn.

Racers' Ring

Racers' Ring enters tapped.
{T}: Add {R} or {G}.
{2}{R}{G}, {T}, Sacrifice Racers' Ring: Draw a card.

Dragon Egg

Defender
When Dragon Egg dies, create a 2/2 red Dragon creature token with flying and "{R}: This creature gets +1/+0 until end of turn."

Ancient Hellkite

Flying
{R}: Ancient Hellkite deals 1 damage to target creature defending player controls. Activate only if Ancient Hellkite is attacking.

Dragon Hatchling

Flying
{R}: Dragon Hatchling gets +1/+0 until end of turn.

Fallaji Dragon Engine

Prototype {2}{R} — 1/3 (You may cast this spell with different mana cost, color, and size. It keeps its abilities and types.)
Flying
{2}: Fallaji Dragon Engine gets +1/+0 until end of turn.

Mountain

Wooded Ridgeline

({T}: Add {R} or {G}.)
Wooded Ridgeline enters tapped.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

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.

Forest

Dragon Mage

Flying
Whenever this creature deals combat damage to a player, each player discards their hand, then draws seven cards.

Drakuseth, Maw of Flames

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

Dragonspeaker Shaman

Dragon spells you cast cost {2} less to cast.

Llanowar Elves

Red Dragon

Flying
Fire Breath — When Red Dragon enters, it deals 4 damage to each opponent.

Rapacious Dragon

Flying
When this creature enters, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")