Claws of Valakut

Enchant creature
Enchanted creature gets +1/+0 for each Mountain you control and has first strike.

Terramorphic Expanse

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Armored Ascension

Enchant creature
Enchanted creature gets +1/+1 for each Plains you control and has flying.

Adventuring Gear

Landfall — Whenever a land you control enters, equipped creature gets +2/+2 until end of turn.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Cosi's Ravager

Landfall — Whenever a land you control enters, you may have this creature deal 1 damage to target player or planeswalker.

Emeria Angel

Flying
Landfall — Whenever a land you control enters, you may create a 1/1 white Bird creature token with flying.

Steppe Lynx

Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Crusher Zendikon

Enchant land
Enchanted land is a 4/2 red Beast creature with trample. It's still a land.
When enchanted land dies, return that card to its owner's hand.

Fledgling Griffin

Landfall — Whenever a land you control enters, this creature gains flying until end of turn.

Kor Skyfisher

Flying
When this creature enters, return a permanent you control to its owner's hand.

Plated Geopede

First strike
Landfall — Whenever a land you control enters, this creature gets +2/+2 until end of turn.

Landbind Ritual

You gain 2 life for each Plains you control.

Plains

Ruin Ghost

{W}, {T}: Exile target land you control, then return it to the battlefield under your control.

Prodigal Pyromancer

{T}: This creature deals 1 damage to any target.

Kor Firewalker

Protection from red
Whenever a player casts a red spell, you may gain 1 life.

Searing Blaze

Searing Blaze deals 1 damage to target player or planeswalker and 1 damage to target creature that player or that planeswalker's controller controls.
Landfall — If you had a land enter the battlefield under your control this turn, Searing Blaze deals 3 damage to that player or planeswalker and 3 damage to that creature instead.

Narrow Escape

Return target permanent you control to its owner's hand. You gain 4 life.

Pilgrim's Eye

Flying
When this creature enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Rest for the Weary

Target player gains 4 life.
Landfall — If you had a land enter the battlefield under your control this turn, that player gains 8 life instead.

Kazuul, Tyrant of the Cliffs

Whenever a creature an opponent controls attacks, if you're the defending player, create a 3/3 red Ogre creature token unless that creature's controller pays {3}.

Geyser Glider

Grotag Thrasher

Whenever this creature attacks, target creature can't block this turn.

Goblin Roughrider

Teetering Peaks

This land enters tapped.
When this land enters, target creature gets +2/+0 until end of turn.
{T}: Add {R}.

Mordant Dragon

Flying
{1}{R}: This creature gets +1/+0 until end of turn.
Whenever this creature deals combat damage to a player, you may have it deal that much damage to target creature that player controls.

Magma Rift

As an additional cost to cast this spell, sacrifice a land.
Magma Rift deals 5 damage to target creature.

Dragon Whelp

Flying
{R}: This creature gets +1/+0 until end of turn. If this ability has been activated four or more times this turn, sacrifice this creature at the beginning of the next end step.

Mountain

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Kor Cartographer

When this creature enters, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.