Highland Lake

This land enters tapped.
{T}: Add {U} or {R}.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Llanowar Elves

Foul Orchard

This land enters tapped.
{T}: Add {B} or {G}.

Dragon's Hoard

Whenever a Dragon you control enters, put a gold counter on this artifact.
{T}, Remove a gold counter from this artifact: Draw a card.
{T}: Add one mana of any color.

Mountain

Woodland Stream

This land enters tapped.
{T}: Add {G} or {U}.

Gleaming Barrier

Defender
When this creature dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

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.

Gift of Paradise

Enchant land
When this Aura enters, you gain 3 life.
Enchanted land has "{T}: Add two mana of any one color."

Clifftop Retreat

This land enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Palladia-Mors, the Ruiner

Flying, vigilance, trample
Palladia-Mors has hexproof if it hasn't dealt damage yet.

Tranquil Expanse

This land enters tapped.
{T}: Add {G} or {W}.

Spit Flame

Spit Flame deals 4 damage to target creature.
Whenever a Dragon you control enters, you may pay {R}. If you do, return this card from your graveyard to your hand.

Forest

Draconic Disciple

{T}: Add one mana of any color.
{7}, {T}, Sacrifice this creature: Create a 5/5 red Dragon creature token with flying.

Verix Bladewing

Kicker {3} (You may pay an additional {3} as you cast this spell.)
Flying
When Verix enters, if it was kicked, create Karox Bladewing, a legendary 4/4 red Dragon creature token with flying.

Demanding Dragon

Flying
When this creature enters, it deals 5 damage to target opponent unless that player sacrifices a creature of their choice.

Rootbound Crag

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.